Exhibit 99.1

Investor Relations:				Media and Analyst Contact:
Brian Norris				CHEN PR
Acme Packet				Chris Carleton
+1.781.328.4790				+1.781.672.3115
bnorris@acmepacket.com				ccarleton@chenpr.com

Acme Packet Reports Record Revenue and Earnings in Second Quarter of 2011

— Second Quarter Revenues of $79.7 million, up 49% Year-Over-Year and 8% Sequentially —

— Second Quarter GAAP EPS of $0.20, up 43% Year-Over-Year —

— Second Quarter Non-GAAP¹ EPS of $0.29, up 53% Year-Over-Year —

— Company Raises 2011 Revenue and Non-GAAP EPS¹ Estimates —

Bedford, Massachusetts — July 21, 2011 — Acme Packet, Inc. (NASDAQ: APKT), the leader in session delivery network solutions, today announced record results for the quarter ended June 30, 2011 and raised its business outlook for 2011. All earnings per share results are on a fully diluted basis unless otherwise noted.

Results for the Second Quarter of 2011

Total revenue in the second quarter of 2011 was $79.7 million, compared to $53.3 million in the second quarter of 2010 and $74.0 million in the first quarter of 2011. Net income in the second quarter of 2011 was $14.0 million, or $0.20 per share, compared to $9.7 million, or $0.14 per share, in the second quarter of 2010 and $13.7 million, or $0.19 per share, in the first quarter of 2011. Net income on a non-GAAP¹ basis in the second quarter of 2011 was $20.4 million, or $0.29 per share, compared to $12.5 million, or $0.19 per share, in the second quarter of 2010, and $18.9 million, or $0.27 per share, in the first quarter of 2011.

Company Raises Business Outlook for 2011

The Company today raised its business outlook for 2011. The Company’s outlook is based on the current indications for its business, which may change at any time. A reconciliation of the Company’s expected GAAP to non-GAAP business outlook, and a statement as to the use of non-GAAP financial measures, is included at the end of this press release.

		Business Outlook for Year Ending December 31, 2011
Estimate		Issued April 26, 2011		Issued July 21, 2011
Total revenue (in millions)		$310-$315		$315-$320
Total revenue growth rate		Approximately 35%		Approximately 36%-38%
Non-GAAP1 EPS		$1.10-$1.15		$1.14-$1.18
Total non-GAAP1 EPS growth rate		Approximately 40%		Approximately 43%-48%
Diluted share count (in millions)		71.5		71.5

Company to Host Live Conference Call and Webcast

The Company’s management team plans to host a live conference call and webcast at 4:30 p.m. eastern time today to discuss the financial results as well as management’s outlook for the business. The conference call may be accessed in the United States by dialing 1.800.230.1093 and using access code “APKT”. The conference call may be accessed outside of the United States by dialing +1.612.288.0337 and using access code “APKT”. The conference call will be simultaneously webcast on the Company’s investor relations website, which can be accessed at www.ir.acmepacket.com. A replay of the conference call will be available approximately two hours after the call by dialing 1.800.475.6701 or +1.320.365.3844 and using access code 209417 or by accessing the webcast replay on the Company’s investor relations website.

¹     A reconciliation of GAAP to non-GAAP results, and a statement on the use of non-GAAP financial measures, is included at the end of this press release.

About Acme Packet

Acme Packet (NASDAQ: APKT), the leader in session delivery network solutions, enables the trusted, first-class delivery of next-generation voice, data and unified communications services and applications across IP networks. Our Net-Net product family fulfills demanding security, service assurance and regulatory requirements in service provider, enterprise and contact center networks. Based in Bedford, Massachusetts, Acme Packet designs and manufactures its products in the USA, selling them through over 150 reseller partners worldwide. More than 1,440 customers in 105 countries have deployed over 13,000 Acme Packet systems, including 90 of the top 100 service providers and 34 of the Fortune 100. For more information visit www.acmepacket.com.

Acme Packet, Inc. Safe Harbor Statement

Statements contained herein that are not historical fact (including those in the section “Company Raises Business Outlook for 2011”) may be forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Such forward-looking statements may relate to, among other things, expected financial and operating results, expected growth rates, future stock-based compensation and amortization expenses, future business prospects and market conditions. Such forward-looking statements do not constitute guarantees of future performance and are subject to a variety of risks and uncertainties that could cause actual results to differ materially from those anticipated. These include, but are not limited to: the amount of stock-based compensation awarded; the applicable Company stock price used to determine stock-based compensation; the exercise pattern of employee stock options; difficulties expanding the Company’s customer base; difficulties leveraging market opportunities; difficulties providing solutions that meet the needs of customers; poor product sales; long sales cycles; difficulties developing new products; difficulties in relationships with vendors and partners; higher risks in international operations; difficulties managing rapid growth; difficulties managing the Company’s financial performance; the ability to hire and retain employees and appropriately staff operations; the Company’s cash needs; the impact of new accounting pronouncements and increased competition. Additional factors that could cause actual results to differ materially from those projected or suggested in any forward-looking statements are contained in the Company’s recent filings with the Securities and Exchange Commission, including those factors discussed under the caption “Risk Factors” in such filings.

Acme Packet, Inc.

Condensed Consolidated Statements of Income
(in thousands, except share and per share data)
(unaudited)

		Three Months Ended June 30,								Six Months Ended June 30,
		2011				2010				2011				2010
Revenue:
Product		$	64,688			$	42,031			$	124,430			$	84,124
Maintenance, support and service			15,045				11,305				29,270				20,262
Total revenue			79,733				53,336				153,700				104,386
Cost of revenue:
Product			11,367				7,434				21,312				14,983
Maintenance, support and service			2,525				2,140				5,531				4,408
Total cost of revenue			13,892				9,574				26,843				19,391
Gross profit			65,841				43,762				126,857				84,995
Operating expenses:
Sales and marketing			24,736				16,623				48,439				33,050
Research and development			12,719				8,646				24,013				17,339
General and administrative			5,788				3,595				10,365				6,879
Merger and integration-related costs			—				—				180				—
Total operating expenses			43,243				28,864				82,997				57,268
Income from operations			22,598				14,898				43,860				27,727
Other (expense) income, net			(196	)			176				(94	)			165
Income before provision for income taxes			22,402				15,074				43,766				27,892
Provision for income taxes			8,394				5,345				16,049				9,830
Net income		$	14,008			$	9,729			$	27,717			$	18,062
Net income per share:
Basic		$	0.21			$	0.16			$	0.42			$	0.30
Diluted		$	0.20			$	0.14			$	0.39			$	0.27
Weighted average number of common shares used in the calculation of net income per share:
Basic			66,141,163				61,488,059				65,623,359				60,659,321
Diluted			71,033,614				67,184,884				70,839,456				66,118,943
Margin:
Gross margin			82.6	%			82.0	%			82.5	%			81.4	%
Operating margin			28.3	%			27.9	%			28.5	%			26.6	%
Net margin			17.6	%			18.2	%			18.0	%			17.3	%

Acme Packet, Inc.

Condensed Consolidated Balance Sheets
(in thousands)
(unaudited)

		June 30,				December 31,
		2011				2010
Assets
Current assets:
Cash and cash equivalents		$	120,571			$	91,669
Short-term investments			192,855				179,024
Accounts receivable, net			53,520				34,797
Inventory			9,721				6,662
Deferred product costs			1,048				3,572
Deferred tax asset			3,814				3,814
Income taxes receivable			14,131				9,979
Other current assets			4,760				3,231
Total current assets			400,420				332,748
Long-term investments			5,000				5,030
Property and equipment, net			21,282				17,156
Acquired intangible assets, net			9,592				9,468
Goodwill			3,269				—
Deferred tax asset, net			14,802				14,802
Other assets			320				940
Total assets		$	454,685			$	380,144
Liabilities and Stockholders’ Equity
Current liabilities:
Accounts payable		$	8,372			$	7,161
Accrued expenses and other current liabilities			9,591				14,629
Deferred revenue			32,897				31,998
Total current liabilities			50,860				53,788
Deferred revenue			1,999				1,546
Deferred rent			4,584				4,265
Stockholders’ equity:
Common stock			73				71
Additional paid-in capital			315,094				266,114
Treasury stock, at cost			(37,522	)			(37,522	)
Other comprehensive income			32				34
Retained earnings			119,565				91,848
Total stockholders’ equity			397,242				320,545
Total liabilities and stockholders’ equity		$	454,685			$	380,144

Condensed Consolidated Statements of Cash Flow
(in thousands)
(unaudited)

		Three Months Ended								Six Months Ended
		June 30,								June 30,
		2011				2010				2011				2010
Cash provided by operating activities		$	8,664			$	15,061			$	20,205			$	23,034
Cash used in investing activities			20,729				22,541				25,002				49,182
Cash provided by financing activities			13,712				17,443				33,699				26,210

Acme Packet, Inc.

Statement on Use of Non-GAAP Financial Measures and
Reconciliation of Non-GAAP Net Income and Non-GAAP Net Income Per Share
(in thousands, except share and per share data)
(unaudited)

          Statement on Use of Non-GAAP Financial Measures:

          To supplement its condensed consolidated financial statements presented in accordance with accounting principles generally accepted in the United States (“GAAP”), the Company discloses certain non-GAAP financial measures, including “non-GAAP net income”, “net income on a non-GAAP basis”, “non-GAAP net income per share”, “non-GAAP EPS” and “net income per share on a non-GAAP basis”. These non-GAAP financial measures are not presented in accordance with GAAP and are not meant to be a substitute for the most directly comparable GAAP measures of “net income”, “EPS” or “net income per share”. Rather, these non-GAAP financial measures should be evaluated in conjunction with its most directly comparable GAAP financial measure and the Company’s financial statements as a whole.

     Management uses these supplemental non-GAAP financial measures to evaluate performance period over period, to analyze the underlying trends in the Company’s business, to assess its performance relative to its competitors, and to establish operational goals and forecasts that are used in allocating resources. Management uses these non-GAAP financial measures because they exclude stock-based compensation expense which is a non-cash charge and related payroll taxes, as well as amortization of acquired intangible assets and merger and integration-related costs associated with the Company’s acquisition activities, all of which are non-operational costs and expenses. By excluding stock-based compensation expense and related payroll taxes, amortization of acquired intangible assets, and merger and integration-related costs, management can compare the Company’s operations to prior periods and to the operations of other companies in its industry who may have materially different unusual, non-operational charges. Management does not consider any of stock-based compensation expense and related payroll taxes, amortization of acquired intangible assets, and merger and integration-related costs to be part of the Company’s operating activities or meaningful in evaluating the Company’s past financial performance or future prospects. Management believes that excluding these items is useful to investors because it is more representative of ongoing costs and therefore more comparable to historical operations.

     Because management uses them, management believes that the disclosure of these non-GAAP financial measures to investors provides greater transparency and useful information to help the investor better understand the Company’s operating performance and to evaluate the methodology used by management to evaluate and measure such performance. Notwithstanding their utility to investors in understanding operational trends, these non-GAAP measures should not be considered measures of the Company’s liquidity. In addition, the Company cautions that its definition of “non-GAAP net income”, “non-GAAP EPS” and “non-GAAP net income per share” may differ from similar measures used by other companies and may differ from period to period. Also, in future periods, management may make other adjustments for expenses and gains that it does not consider reflective of core operating performance in a particular period thereby modifying its definition of “non-GAAP net income”, “non-GAAP EPS” and “non-GAAP net income per share” by excluding these other or additional expenses and gains.

Acme Packet, Inc.

Non-GAAP Condensed Consolidated Statements of Income
(in thousands, except share and per share data)
(unaudited)

		Three Months Ended June 30,								Six Months Ended June 30,
		2011				2010				2011				2010
Revenue:
Product		$	64,688			$	42,031			$	124,430			$	84,124
Maintenance, support and service			15,045				11,305				29,270				20,262
Total revenue			79,733				53,336				153,700				104,386
Cost of revenue:
Product			10,504				6,864				19,816				13,861
Maintenance, support and service			2,026				1,897				4,581				3,933
Total cost of revenue			12,530				8,761				24,397				17,794
Gross profit			67,203				44,575				129,303				86,592
Operating expenses:
Sales and marketing			20,155				14,750				40,233				29,550
Research and development			10,056				7,416				19,096				14,923
General and administrative			4,485				3,072				8,082				5,930
Total operating expenses			34,696				25,238				67,411				50,403
Income from operations			32,507				19,337				61,892				36,189
Other (expense) income, net			(196	)			176				(94	)			165
Income before provision for income taxes			32,311				19,513				61,798				36,354
Provision for income taxes			11,881				7,043				22,429				13,171
Net income		$	20,430			$	12,470			$	39,369			$	23,183
Net income per share:
Basic		$	0.31			$	0.20			$	0.60			$	0.38
Diluted		$	0.29			$	0.19			$	0.56			$	0.35
Weighted average number of common shares used in the calculation of net income per share:
Basic			66,141,163				61,488,059				65,623,359				60,659,321
Diluted			71,033,614				67,184,884				70,839,456				66,118,943
Margin:
Gross margin			84.3	%			83.6	%			84.1	%			83.0	%
Operating margin			40.8	%			36.3	%			40.3	%			34.7	%
Net margin			25.6	%			23.4	%			25.6	%			22.2	%

Reconciliation of Non-GAAP Net Income and Non-GAAP Net Income Per Share for the Three Months Ended June 30, 2011, March 31, 2011, and June 30, 2010 and the Six Months Ended June 30, 2011 and June 30, 2010 (unaudited):

Acme Packet, Inc.

GAAP to Non-GAAP Reconciliation
Three Months Ended June 30, 2011
(in thousands, except share and per share data)
(unaudited)

		GAAP				Stock-based compensation expense and related payroll taxes				Amortization of acquired intangible assets					Non-GAAP1
Revenue:
Product		$	64,688			$	—			$	—			$	64,688
Maintenance, support and service			15,045				—				—				15,045
Total revenue			79,733				—				—				79,733
Cost of revenue:
Product			11,367				(327	)			(536	)			10,504
Maintenance, support and service			2,525				(499	)			—				2,026
Total cost of revenue			13,892				(826	)			(536	)			12,530
Gross profit			65,841				826				536				67,203
Operating expenses:
Sales and marketing			24,736				(4,441	)			(140	)			20,155
Research and development			12,719				(2,652	)			(11	)			10,056
General and administrative			5,788				(1,303	)			—				4,485
Total operating expenses			43,243				(8,396	)			(151	)			34,696
Income from operations			22,598				9,222				687				32,507
Other (expense), net			(196	)			—				—				(196	)
Income before provision for income taxes			22,402				9,222				687				32,311
Provision for income taxes			8,394				3,241				246				11,881
Net income		$	14,008			$	5,981			$	441			$	20,430
Net income per share:
Basic		$	0.21			$	0.09			$	0.01			$	0.31
Diluted		$	0.20			$	0.08			$	0.01			$	0.29
Weighted average number of common shares used in the calculation of net income per share:
Basic			66,141,163				66,141,163				66,141,163				66,141,163
Diluted			71,033,614				71,033,614				71,033,614				71,033,614
Margin:
Gross margin			82.6	%											84.3	%
Operating margin			28.3	%											40.8	%
Net margin			17.6	%											25.6	%

Acme Packet, Inc.
GAAP to Non-GAAP Reconciliation
Three Months Ended June 30, 2010
(in thousands, except share and per share data)
(unaudited)

						Stock-based
						compensation				Amortization of
						expense and				acquired
						related payroll				intangible
		GAAP				taxes				assets				Non-GAAP1
Revenue:
Product		$	42,031			$	—			$	—			$	42,031
Maintenance, support and service			11,305				—				—				11,305
Total revenue			53,336				—				—				53,336
Cost of revenue:
Product			7,434				(191	)			(379	)			6,864
Maintenance, support and service			2,140				(243	)			—				1,897
Total cost of revenue			9,574				(434	)			(379	)			8,761
Gross profit			43,762				434				379				44,575
Operating expenses:
Sales and marketing			16,623				(1,828	)			(45	)			14,750
Research and development			8,646				(1,219	)			(11	)			7,416
General and administrative			3,595				(523	)			—				3,072
Total operating expenses			28,864				(3,570	)			(56	)			25,238
Income from operations			14,898				4,004				435				19,337
Other income, net			176				—				—				176
Income before provision for income taxes			15,074				4,004				435				19,513
Provision for income taxes			5,345				1,544				154				7,043
Net income		$	9,729			$	2,460			$	281			$	12,470
Net income per share:
Basic		$	0.16			$	0.04			$	0.00			$	0.20
Diluted		$	0.14			$	0.04			$	0.00			$	0.19
Weighted average number of common shares used in the calculation of net income per share:
Basic			61,488,059				61,488,059				61,488,059				61,488,059
Diluted			67,184,884				67,184,884				67,184,884				67,184,884
Margin:
Gross margin			82.0	%											83.6	%
Operating margin			27.9	%											36.3	%
Net margin			18.2	%											23.4	%

Acme Packet, Inc.
GAAP to Non-GAAP Reconciliation
Six Months Ended June 30, 2011
(in thousands, except share and per share data)
(unaudited)

						Stock-based
						compensation				Amortization of
						expense and				acquired				Merger and
						related payroll				intangible				integration-
		GAAP				taxes				assets				related costs				Non-GAAP1
Revenue:
Product		$	124,430			$	—			$	—			$	—			$	124,430
Maintenance, support and service			29,270				—				—				—				29,270
Total revenue			153,700				—				—				—				153,700
Cost of revenue:
Product			21,312				(589	)			(907	)			—				19,816
Maintenance, support and service			5,531				(950	)			—				—				4,581
Total cost of revenue			26,843				(1,539	)			(907	)			—				24,397
Gross profit			126,857				1,539				907				—				129,303
Operating expenses:
Sales and marketing			48,439				(8,020	)			(186	)			—				40,233
Research and development			24,013				(4,894	)			(23	)			—				19,096
General and administrative			10,365				(2,283	)			—				—				8,082
Merger and integration-related costs			180				—				—				(180	)			-
Total operating expenses			82,997				(15,197	)			(209	)			(180	)			67,411
Income from operations			43,860				16,736				1,116				180				61,892
Other (expense), net			(94	)			—				—				—				(94	)
Income before provision for income taxes			43,766				16,736				1,116				180				61,798
Provision for income taxes			16,049				5,978				402				—				22,429
Net income		$	27,717			$	10,758			$	714			$	180			$	39,369
Net income per share:
Basic		$	0.42			$	0.16			$	0.01			$	0.00			$	0.60
Diluted		$	0.39			$	0.15			$	0.01			$	0.00			$	0.56
Weighted average number of common shares used in the calculation of net income per share:
Basic			65,623,359				65,623,359				65,623,359				65,623,359				65,623,359
Diluted			70,839,456				70,839,456				70,839,456				70,839,456				70,839,456
Margin:
Gross margin			82.5	%															84.1	%
Operating margin			28.5	%															40.3	%
Net margin			18.0	%															25.6	%

Acme Packet, Inc.
GAAP to Non-GAAP Reconciliation
Six Months Ended June 30, 2010
(in thousands, except share and per share data)
(unaudited)

						Stock-based
						compensation				Amortization of
						expense and				acquired
						related payroll				intangible
		GAAP				taxes				assets				Non-GAAP1
Revenue:
Product		$	84,124			$	—			$	—			$	84,124
Maintenance, support and service			20,262				—				—				20,262
Total revenue			104,386				—				—				104,386
Cost of revenue:
Product			14,983				(364	)			(758	)			13,861
Maintenance, support and service			4,408				(475	)			—				3,933
Total cost of revenue			19,391				(839	)			(758	)			17,794
Gross profit			84,995				839				758				86,592
Operating expenses:
Sales and marketing			33,050				(3,410	)			(90	)			29,550
Research and development			17,339				(2,394	)			(22	)			14,923
General and administrative			6,879				(949	)			—				5,930
Total operating expenses			57,268				(6,753	)			(112	)			50,403
Income from operations			27,727				7,592				870				36,189
Other income, net			165				—				—				165
Income before provision for income taxes			27,892				7,592				870				36,354
Provision for income taxes			9,830				3,035				306				13,171
Net income		$	18,062			$	4,557			$	564			$	23,183
Net income per share:
Basic		$	0.30			$	0.08			$	0.01			$	0.38
Diluted		$	0.27			$	0.07			$	0.01			$	0.35
Weighted average number of common shares used in the calculation of net income per share:
Basic			60,659,321				60,659,321				60,659,321				60,659,321
Diluted			66,118,943				66,118,943				66,118,943				66,118,943
Margin:
Gross margin			81.4	%											83.0	%
Operating margin			26.6	%											34.7	%
Net margin			17.3	%											22.2	%

Acme Packet, Inc.
GAAP to Non-GAAP Reconciliation
Three Months Ended March 31, 2011
(in thousands, except share and per share data)
(unaudited)

						Stock-based
						compensation				Amortization of
						expense and				acquired				Merger and
						related payroll				intangible				integration-
		GAAP				taxes				assets				related costs				Non-GAAP1
Revenue:
Product		$	59,742			$	—			$	—			$	—			$	59,742
Maintenance, support and service			14,225				—				—				—				14,225
Total revenue			73,967				—				—				—				73,967
Cost of revenue:
Product			9,945				(262	)			(371	)			—				9,312
Maintenance, support and service			3,006				(451	)			—				—				2,555
Total cost of revenue			12,951				(713	)			(371	)			—				11,867
Gross profit			61,016				713				371				—				62,100
Operating expenses:
Sales and marketing			23,703				(3,579	)			(46	)			—				20,078
Research and development			11,294				(2,242	)			(12	)			—				9,040
General and administrative			4,577				(980	)			—				—				3,597
Merger and integration-related costs			180				—				—				(180	)			—
Total operating expenses			39,754				(6,801	)			(58	)			(180	)			32,715
Income from operations			21,262				7,514				429				180				29,385
Other income, net			102				—				—				—				102
Income before provision for income taxes			21,364				7,514				429				180				29,487
Provision for income taxes			7,655				2,737				156				—				10,548
Net income		$	13,709			$	4,777			$	273			$	180			$	18,939
Net income per share:
Basic		$	0.21			$	0.07			$	0.00			$	0.00			$	0.29
Diluted		$	0.19			$	0.07			$	0.00			$	0.00			$	0.27
Weighted average number of common shares used in the calculation of net income per share:
Basic			65,076,303				65,076,303				65,076,303				65,076,303				65,076,303
Diluted			70,476,973				70,476,973				70,476,973				70,476,973				70,476,973
Margin:
Gross margin			82.5	%															84.0	%
Operating margin			28.7	%															39.7	%
Net margin			18.5	%															25.6	%