Exhibit 99.1

Primus Telecommunications Group, Incorporated

Reports Second Quarter 2011 Results

MCLEAN, VA – (MARKET WIRE) – August 15, 2011 – Primus Telecommunications Group, Incorporated (PTGi) (NYSE: PTGI), a global facilities-based integrated provider of advanced telecommunications products and services, announced results for the second quarter ended June 30, 2011. PTGi completed the acquisition of Arbinet Corporation on February 28, 2011; therefore, second quarter 2011 comparisons are not directly comparable with prior periods.

Consolidated Results

Net revenue for the second quarter 2011 was $282.5 million, an increase of 45.2% from second quarter 2010 net revenue of $194.6 million. Net revenue includes a $73.1 million contribution from Arbinet. Adjusted EBITDA was $19.9 million, a decrease of 13.1% from second quarter 2010 Adjusted EBITDA of $22.9 million. The impact of foreign exchange translation was a positive $23.6 million to revenue for the second quarter 2011 and a positive $2.4 million to Adjusted EBITDA. Free cash flow decreased in the quarter to negative $8.5 million from second quarter 2010 negative free cash flow of $7.0 million. Free cash flow in the second quarters of 2011 and 2010 includes interest payments of $16.5 million and $17.2 million, respectively.

Peter D. Aquino, Chairman, President and Chief Executive Officer, stated, “PTGi took significant steps forward during the second quarter 2011 with several key accomplishments. With the transformation of our balance sheet, we can progress in executing our strategy to continue to improve operations, generate additional free cash flow given interest savings achieved and unlock the value in the sum of the parts. In addition, we are very excited to be recently listed as PTGi on the NYSE to broaden investment in the company and to have named Ken Schwarz as our new CFO. Overall, it was an action packed quarter that better positions the company to pursue our objectives for the year.”

Key Second Quarter 2011 Accomplishments

Second Quarter 2011 Net Revenue by Major Operating Segment

Canada – Net revenue of $64.1 million increased 10.4% from $58.0 million in the second quarter 2010. The impact of foreign currency translation was a positive $3.8 million. On a constant currency basis, net revenue increased 3.9% as increases in local, Internet, VoIP, and data and hosting services were partially offset by declines in retail long distance and prepaid voice.

Australia – Net revenue of $73.7 million increased 9.2% from $67.5 million in second quarter 2010. The impact of foreign currency translation was a positive $12.4 million. On a constant currency basis, net revenue decreased 9.2% as decreases in business and residential voice, Internet and DSL services were partially offset by increases in data center, wireless and VoIP.

International Carrier Services – Net revenue of $126.5 million increased 157.2% from $49.2 million in second quarter 2010, primarily due to including a full quarter of Arbinet net revenue of $73.1 million. The impact of foreign currency translation was a positive $6.6 million. Excluding Arbinet and on a constant currency basis, net revenue increased 3.3%.

United States – Net revenue of $10.7 million decreased 16.4% from $12.8 million in second quarter 2010, primarily due to decreases in retail voice and VoIP.

Other Businesses –

Brazil – Net revenue of $7.3 million increased 3.5% from $7.1 million in second quarter 2010. The impact of foreign currency translation was a positive $0.8 million. On a constant currency basis, net revenue decreased 8.3% due primarily to decreases in carrier voice services.

Further Second Quarter 2011 Detail

Net revenue less cost of revenue was $77.0 million, or 27.2% of net revenue, compared to $70.6 million, or 36.3% of net revenue, in second quarter 2010. Net revenue less cost of revenue, as a percentage of net revenue, was negatively impacted primarily by the addition of lower margin Arbinet customers. Lower retail voice usage revenues in Australia and lower prepaid card margins in Canada also contributed to the decline.

Selling, general and administrative (SG&A) expense was $59.4 million, or 21.0% of net revenue, in the second quarter 2011 compared to $47.9 million, or 24.6% of net revenue in second quarter 2010. Included in second quarter 2011 SG&A were integration and costs for M&A-related professional services of $1.1 million and $3.6 million of SG&A expense from Arbinet.

Income from operations of $0.5 million compared to income of $4.8 million in the second quarter 2010. Depreciation and amortization expense was $17.1 million as compared to $18.2 million in second quarter 2010. This reduction is due to fully depreciating and amortizing fixed assets and customer lists that were re-valued as part of fresh start accounting upon emergence from bankruptcy, offset, in part, by additional depreciation and amortization from Arbinet. It is expected that depreciation and amortization expense related to the pre-bankruptcy assets will continue to run off at an accelerated pace over the next two years.

Adjusted EBITDA was $19.9 million, or 7.0% of net revenue, compared to $22.9 million, or 11.8% of net revenue, in the second quarter 2010. Second quarter 2011 Adjusted EBITDA excluding integration and costs for M&A-related professional services was $21.0 million.

Net loss was $6.3 million, or $(0.48) per basic and diluted common share, compared to $13.0 million, or $(1.34) per basic and diluted common share in the second quarter 2010. The number of shares outstanding used to calculate basic and diluted earnings per common share in the second quarter of 2011 was 13.4 million compared to 9.7 million for basic and diluted earnings per common share in the second quarter 2010.

Balance Sheet, Liquidity and Capital Resources

PTGi ended the second quarter 2011 with $31.5 million in unrestricted cash and cash equivalents, down from $65.6 million at March 31, 2011. Cash was generated during the second quarter in the following amounts: $19.9 million of Adjusted EBITDA, offset by the usage of $24.0 million used to redeem 14.25% Senior Subordinated Secured Notes due 2013, $16.5 million in interest payments, $4.9 million used in working capital primarily caused by a temporary delay in receivables collection due a Canadian postal strike now ended, $7.5 million for capital expenditures, and a $1.2 million dividend paid to our non-controlling interest shareholder.

The principal amount of PTGi’s long-term obligations as of June 30, 2011 was $221.2 million, down from $245.7 million as of December 31, 2010.

Free Cash Flow in the second quarter 2011 was negative $8.5 million compared to negative free cash flow of $7.0 million in the second quarter 2010. Higher capital expenditures were primary contributors to the decrease in free cash flow over the prior year quarter. PTGi defines Free Cash Flow as net cash provided by operating activities less cash used in the purchase of property and equipment.

Ken Schwarz, Chief Financial Officer, stated, “Second quarter 2011 results include major progress on all fronts, strategically, financially and operationally. The balance sheet improvement and the additional flexibility our new debt agreement permits are designed to pave the way toward improved free cash flow. This quarter’s cash balance reflects a payout of $16.5 million of interest associated with our recent Note exchange, with our next interest payment due on October 15^th at the lower rate.”

Conference Call

The Company will hold a conference call and webcast on August 16, 2011 at 8:30 AM ET. To access the call, please dial 866-305-6438 (toll free) or 706-679-7161 approximately 10 minutes prior to the start of the conference call. The conference call will also be broadcast live over the Internet with an accompanying slide presentation, which can be accessed via the Investor Relations section of PTGi’s web site at www.ptgi.com. The webcast and slide presentation will be available for replay for 90 days at www.ptgi.com.

A telephonic replay of this conference call will also be available by dialing 855-859-2056 (toll free) or 404-537-3406 (access code: 84339211) from 12:30 PM ET on August 16, 2011 until midnight ET on August 22, 2011.

About PTGi

PTGi is a leading provider of advanced communication solutions, including, traditional and IP voice, data, mobile services, broadband Internet, collocation, hosting, and outsourced managed services to business and residential customers in the United States, Canada, Australia, and Brazil. PTGi is also one of the leading international wholesale service providers to fixed and mobile network operators worldwide. PTGi owns and operates its own global network of next-generation IP soft switches, media gateways, hosted IP/SIP platforms, broadband infrastructure, fiber capacity, and data centers located in Canada, Australia, and Brazil. Founded in 1994, PTGi is headquartered in McLean, Virginia. For more information, visit http://www.ptgi.com.

Non-GAAP Financial Measures

This release includes certain non-GAAP financial measures as defined under SEC rules, which include Adjusted EBITDA and Free Cash Flow. PTGi has provided a reconciliation of these measures to the most directly comparable GAAP measures, which is contained in the tables to this release. Additionally, information regarding the purpose and use for these non-GAAP financial measures is set forth in our Form 8-K disclosing this press release.

Cautionary Statement Regarding Forward-Looking Statements

This press release contains or incorporates a number of “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 statements are based on current expectations, and are not strictly historical statements. In some cases, you can identify forward-looking statements by terminology such as “if,” “may,” “should,” “believe,” “anticipate,” “future,” “forward,” “potential,” “estimate,” “reinstate,” “opportunity,” “goal,” “objective,” “exchange,” “growth,” “outcome,” “could,” “expect,” “intend,” “plan,” “strategy,” “provide,” “commitment,” “result,” “seek,” “pursue,” “ongoing,” “include” or in the negative of such terms or comparable terminology. These forward-looking statements inherently involve certain risks and uncertainties, although they are based on our current plans or assessments which are believed to be reasonable as of the date of this press release. Forward-looking statements in this press release include, among others, statements regarding: our liquidity and debt service forecast; our financing, refinancing, debt extension, de-leveraging, restructuring, exchange or tender plans or initiatives, and potential dilution of existing equity holders from such initiatives; our expectations regarding our continued ability to generate free cash flow; our ability to successfully integrate the Arbinet business and realize anticipated synergies; our expectations regarding increased competitive pressures, declining usage patterns and our growth products, bundled service offerings, the pace and cost of customer migration onto our networks, the effectiveness and profitability of the growth products; our assumptions regarding currency exchange rates; and the timing, extent and effectiveness of our cost reduction initiatives and management’s ability to moderate or control discretionary spending. While PTGi believes the forward-looking statements

contained in this press release are accurate, there are a number of factors that could cause actual events or results to differ materially from those indicated by such forward-looking statements. Those risks and uncertainties include, among other things, the risks listed under “Risk Factors” in PTGi’s annual report and quarterly reports filed with the Securities and Exchange Commission and available through the company’s website at www.ptgi.com. PTGi disclaims any obligation to update the information contained in this press release as new information becomes available.

Investor Contact:

PTGi

Richard Ramlall, SVP Corporate Development and Chief Communications Officer

703-748-8050

ir@ptgi.com

Lippert/Heilshorn & Assoc., Inc.

Carolyn Capaccio

212-838-3777

ccapaccio@lhai.com

(tables follow)

PRIMUS TELECOMMUNICATIONS GROUP, INCORPORATED

CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS

(in thousands, except per share amounts)

(unaudited)

PRIMUS TELECOMMUNICATIONS GROUP, INCORPORATED

CONSOLIDATED CONDENSED BALANCE SHEET

(in thousands)

(unaudited)

PRIMUS TELECOMMUNICATIONS GROUP, INCORPORATED

RECONCILIATION OF NET INCOME (LOSS) TO ADJUSTED EBITDA

(in thousands)

(unaudited)

PRIMUS TELECOMMUNICATIONS GROUP, INCORPORATED

RECONCILIATION OF NET CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES

TO FREE CASH FLOW

(in thousands)

(unaudited)