Exhibit 99.1

OPNET Announces Record Financial Results for Fourth Quarter of Fiscal 2011

June Dividend Increased to $0.12 Per Share

BETHESDA, MD—May 09, 2011—OPNET Technologies, Inc. (NASDAQ: OPNT), a leading provider of solutions for application and network performance management, today announced that revenue for the fourth fiscal quarter, ended March 31, 2011, was $41.1 million, compared to $34.4 million for the same quarter in the prior fiscal year. Diluted earnings per share for the fourth quarter of fiscal 2011 were $0.17, compared to $0.11 for the same quarter in the prior fiscal year. The Company also announced today a quarterly dividend of $0.12 per share, which represents one quarter of the Company’s fiscal 2012 annual dividend target of $0.48, payable on June 29, 2011 to stockholders of record as of the close of business on June 15, 2011. During fiscal 2011, the Company paid aggregate quarterly dividends of $0.40 per share and a one-time special dividend of $0.75 per share.

Marc A. Cohen, OPNET’s Chairman and CEO, stated, “We are very pleased to report strong execution both for the fourth quarter of fiscal 2011 and for the entire fiscal year. Our strong performance was driven by our success in addressing the multi-billion dollar application performance management (APM) market. During our fourth quarter, we set new records, including total revenue of $41.1 million, product revenue of $21.6 million, total cash, cash equivalents and marketable securities of $114.7 million, and deferred revenue of $47.5 million. During fiscal 2011, we grew product revenue year-over-year by 39% and more than doubled our operating income from $8.1 million to $18.8 million.”

Mr. Cohen continued, “APM product sales accounted for 63% of our total product bookings during the quarter, and increased 41% over the same quarter last year. APM product sales accounted for 68% of our total product bookings during fiscal 2011, and increased 38% over fiscal 2010. We believe that the growth in APM is being driven by both superior analytics, and our end-to-end solutions that span networks, applications, and systems. We further believe that these competitive advantages can generate sustained growth in product revenue and profitability over the long term.”

The Company’s fourth quarter fiscal 2011 financial results are presented below. The non-GAAP results exclude the income statement effects of stock-based compensation and acquisition-related amortization of intangible assets. A reconciliation of GAAP results to non-GAAP results has been provided in the financial statement table following the text of the press release. For further information, please refer to the section of the press release titled “Use of Non-GAAP Measures.”

GAAP Financial Highlights for the Fourth Quarter of Fiscal 2011:

Non-GAAP Financial Highlights for the Fourth Quarter of Fiscal 2011:

First Quarter Fiscal Year 2012 Financial Outlook

OPNET currently expects fiscal 2012 first quarter GAAP revenue to be between $37.0 million and $40.0 million, and GAAP diluted net income per common share to be between $0.10 and $0.17 and non-GAAP diluted net income per common share to be between $0.13 and $0.20. The non-GAAP diluted net income per common share expectation excludes approximately $663,000 of expense associated with stock-based compensation expense, amortization of acquired intangible assets, and the related impact of these adjustments on the provision for income taxes. These estimates represent management’s current expectations about the Company’s future financial performance, based on information available at this time.

OPNET will hold an investor conference call on Monday, May 9, 2011 at 5:00 pm Eastern Time to review financial results for the fourth quarter of fiscal 2011.

To listen to the OPNET investor conference call:

To listen to the archived call:

Use of Non-GAAP Measures

OPNET uses a variety of financial measures that are not in accordance with generally accepted accounting principles, or GAAP, as supplemental measures to GAAP to evaluate its operational performance. These financial measures, which include non-GAAP gross profit, non-GAAP operating income, non-GAAP operating margin, non-GAAP net income and non-GAAP diluted earnings per share, exclude the impact of certain items and, therefore, have not been calculated in accordance with GAAP. A detailed explanation of each of the adjustments to such financial measures is described below. A reconciliation of each of these non-GAAP financial measures to its most comparable GAAP financial measure is also included below.

Management uses non-GAAP financial measures (a) to evaluate OPNET’s historical and prospective financial performance as well as its performance relative to its competitors, and (b) to measure operational profitability and the accuracy of forecasting. In addition, many financial analysts who follow OPNET focus on and publish both historical results and future projections based on non-GAAP financial measures. OPNET believes that it is in the best interest of its investors to provide this information to analysts so that they accurately report the non-GAAP financial information. Moreover, investors have historically requested these non-GAAP financial measures as a means of providing consistent and comparable information with past reports of financial results.

While management believes that these non-GAAP financial measures provide useful supplemental information to investors, there are limitations associated with the use of these non-GAAP financial measures. These non-GAAP financial measures are not prepared in accordance with GAAP, are not reported by all of OPNET’s competitors and may not be directly comparable to similarly titled measures of OPNET’s competitors due to potential differences in the exact method of calculation. OPNET compensates for these limitations by using these non-GAAP financial measures only as supplements to GAAP financial measures and by providing the reconciliations of the non-GAAP financial measures to their most comparable GAAP financial measures.

The adjustments we use to derive these non-GAAP financial measures, and the basis for such adjustments, are outlined below:

Amortization of intangibles and its related tax impact. OPNET incurs amortization of intangibles related to various acquisitions it has made in recent years. This amortization is included in the following line items of its GAAP presentation:

Management excludes these expenses and their related tax impact for the purpose of calculating non-GAAP operating income, non-GAAP gross profit, non-GAAP operating margin, non-GAAP net income and non-GAAP diluted earnings per share when it evaluates the continuing operational performance of OPNET because these costs are fixed at the time of an acquisition, are then amortized over a period of three to five years after the acquisition and generally cannot be changed or influenced by management after the acquisition. Accordingly, management does not consider these expenses for purposes of evaluating the performance of OPNET during the applicable time period after a given acquisition, and it excludes such expenses when evaluating OPNET’s financial performance.

Stock-based compensation expense and its related tax impact. OPNET incurs expense related to stock-based compensation, which is included in the following line items of its GAAP presentation:

Although stock-based compensation is an expense of OPNET and is viewed as a form of compensation, management excludes these expenses for the purpose of calculating non-GAAP operating income, non-GAAP gross profit, non-GAAP operating margin, non-GAAP net income and non-GAAP diluted earnings per share when it evaluates the continuing operational performance of OPNET. Specifically, OPNET excludes stock-based compensation during its quarterly and annual assessments of OPNET’s and management’s performance. In evaluating the performance of senior management, stock-based compensation is excluded from expenditure and profitability results.

Diluted weighted average common shares outstanding. Non-GAAP diluted net income per common share reflects the elimination of amortization of intangibles, stock-based compensation expense and the related tax impacts, all as discussed above. In addition, in cases in which the non-GAAP net income changes from negative to positive when compared to the GAAP net income, or vice versa, the non-GAAP per-share calculation also gives effect to an adjustment to the number of diluted weighted average common shares outstanding reflecting the application of the treasury method and the fact that shares previously considered anti-dilutive would now be considered dilutive, or vice versa.

About OPNET Technologies, Inc.

Founded in 1986, OPNET Technologies, Inc. (NASDAQ:OPNT) is a leading provider of application and network performance management solutions. For more information about OPNET and its products, visit www.opnet.com.

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OPNET, OPNET Technologies, Inc., AppMapper Xpert, AppResponse Xpert, and AppInternals Xpert are trademarks of OPNET Technologies, Inc. All other trademarks are the property of their respective owners.

Statements in this press release that are not purely historical facts may constitute forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995. OPNET Technologies, Inc. (“OPNET”) assumes no obligation to update such statements. Forward-looking statements, including statements regarding the impact of enhancements to our APM product portfolio or our competitive position and statements concerning expected revenue and diluted net income per common share and Non-GAAP diluted net income per common share for the first quarter of fiscal 2012, are predictions based upon information available to OPNET as of the date of this press release and involve risks and uncertainties; therefore, actual events or results may differ materially. Factors that may cause OPNET’s actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by such forward-looking statements include, among others, those factors listed under the caption “Risk Factors” in OPNET’s Annual Report on Form 10-K for the fiscal year ended March 31, 2010, as filed with the Securities and Exchange Commission on June 4, 2010, as updated from time to time in subsequent SEC filings. The risk factors set forth in the Company’s Form 10-K under the caption “Risk Factors,” as updated from time to time in subsequent SEC filings, are specifically incorporated by reference into this press release. The Company undertakes no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Note to editors: The word OPNET is spelled with all upper-case letters.

OPNET TECHNOLOGIES, INC.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands, except per share data)

(unaudited)

OPNET TECHNOLOGIES, INC.

RECONCILIATION OF GAAP TO NON-GAAP INCOME

(in thousands, except per share data)

(unaudited)

OPNET TECHNOLOGIES, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(in thousands, except per share data)

(unaudited)