Exhibit 99.1

CAMBRIDGE, Mass. – August 9, 2011 – Pegasystems Inc. (NASDAQ: PEGA) today announced financial results for the second quarter and six months ended June 30, 2011. GAAP revenue for the second quarter of 2011 increased 26% to $103.5 million compared to the second quarter of 2010. GAAP net income for the second quarter of 2011 was $2.3 million, or $0.06 per diluted share, compared to GAAP net loss of ($8.2) million, or ($0.22) per diluted share, for the second quarter of 2010. Non-GAAP net income for the second quarter of 2011 was $6.3 million, or $0.16 per diluted share, compared to Non-GAAP net income of $3.8 million, or $0.10 per diluted share, for the second quarter of 2010.

SELECTED GAAP & NON-GAAP RESULTS (1)

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Business Perspective

“We continue to expand Pega’s role with clients, helping them become more customer-centric, eliminate operational silos, and seize opportunities more rapidly,” said Alan Trefler, Founder and CEO of Pegasystems. “At our PegaWORLD conference in June, dozens of customer speakers shared their successes with more than 1,600 attendees. We also announced a significant new release of our core Pega BPM solution at PegaWORLD, featuring increased power and ease of use. This offering is the first BPM solution to seamlessly enable unified predictive decisioning and analytics, empowering organizations to optimize the overall customer experience for revenue growth and retention.”

“The power of Pega BPM is driving increased adoption in new industries and creating major new relationships with the world’s leading Systems Integrators. We continued to increase our portfolio of industry-specific customer service solutions throughout the quarter, which enable our clients and partners to achieve rapid time-to-value while leveraging the agility of our unique Build for Change^® technology. We are pleased at the expansive use of Pega BPM by both our new and existing clients, and see that Pega’s ability to improve both customer service and operational efficiency is a winning combination,” concluded Mr. Trefler.

Craig Dynes, Pegasystems’ CFO, added, “The pace of our business continues to increase as the value of license arrangements executed in Q2, 2011 increased compared to Q1, 2011 and was significantly higher compared to Q2, 2010. We are pleased that we exceeded $100 million in quarterly revenue again while also building significant backlog and increasing our pipeline. We’ve had a great start to 2011, and are focused on driving business growth for the rest of the year and 2012.”

Messrs. Trefler and Dynes will host a conference call and live Webcast associated with this announcement at 6:00 p.m. EDT on August 9, 2011. Dial-in information is as follows: 1 (866) 393-1604 (domestic) or 1 (678) 809-1046 (international). To listen to the Webcast log onto www.pega.com at least 5 minutes prior to the event’s broadcast and click on the Webcast icon in the Investor Relations section. A replay of the call will also be available on www.pega.com in the Investor Relations section Audio Archives link.

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Discussion of Non-GAAP Measures

To supplement financial results presented on a GAAP basis, the Company provides Non-GAAP measures included in this release, including the tables contained herein. Pegasystems’ management utilizes a number of different financial measures, both GAAP and Non-GAAP, in analyzing and assessing the overall performance of the business, for making operating decisions, and for forecasting and planning for future periods. The Company’s annual financial plan is prepared both on a GAAP and Non-GAAP basis, and the Non-GAAP annual financial plan is approved by our board of directors. In addition and as a consequence of the importance of these measures in managing the business, the Company uses Non-GAAP measures and results in the evaluation process to establish management’s compensation.

The Non-GAAP measures exclude certain business combination accounting entries and expenses related to our acquisition of Chordiant, as well as other significant expenses including stock-based compensation. The Company believes that these Non-GAAP measures are helpful in understanding our past financial performance and our anticipated future results. These Non-GAAP financial measures are not meant to be considered in isolation or as a substitute for comparable GAAP measures and should be read only in conjunction with our consolidated financial statements prepared in accordance with GAAP. A reconciliation of the Company’s GAAP to Non-GAAP measures is included in the financial schedules at the end of the release.

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Forward-Looking Statements

Certain statements contained in this press release may be construed as “forward-looking statements” as defined in the Private Securities Litigation Reform Act of 1995, including those relating to our revenue, net income and earnings per share. The words “anticipate,” “project,” “expect,” “plan,” “intend,” “believe,” “estimate,” “should”, “target,” “forecast,” “could,” “preliminary,” “guidance” and similar expressions, among others, identify forward-looking statements, which speak only as of the date the statement was made. These statements are based on current expectations and assumptions and involve various risks and uncertainties, which could cause the Company’s actual results to differ from those expressed in such forward-looking statements. These risks and uncertainties include, among others, variation in demand for our products and services and the difficulty in predicting the completion of product acceptance and other factors affecting the timing of our license revenue recognition, the mix of perpetual and term licenses and the level of term license renewals, our ability to develop new products and evolve existing ones, the ongoing consolidation in the financial services and healthcare markets, our ability to attract and retain key personnel, reliance on key third party relationships, the potential loss of vendor specific objective evidence for our professional services, and management of the Company’s growth. Further information regarding these and other factors which could cause the Company’s actual results to differ materially from any forward-looking statements contained in this press release is contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2010 and other recent filings with the Securities and Exchange Commission. The forward-looking statements contained in this press release represent the Company’s views as of August 9, 2011. Investors are cautioned not to place undue reliance on such forward-looking statements and there are no assurances that the matters contained in such statements will be achieved. Although subsequent events may cause the Company’s view to change, the Company does not undertake and specifically disclaims any obligation to publicly update or revise these forward-looking statements whether as the result of new information, future events or otherwise. The statements should therefore not be relied upon as representing the Company’s view as of any date subsequent to August 9, 2011.

About Pegasystems

Pegasystems, the leader in business process management and software for customer centricity, helps organizations enhance customer loyalty, generate new business, and improve productivity. Our patented Build for Change^® technology speeds the delivery of critical business solutions by directly capturing business objectives and eliminating manual programming. Pegasystems enables clients to quickly adapt to changing business conditions in order to outperform the competition. For more information, please visit us at www.pega.com.

For Information, contact:

Craig Dynes, Chief Financial Officer

617-866-6020

CDynes@pega.com

All trademarks are the property of their respective owners.

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Pegasystems Inc.

Unaudited Condensed Consolidated Statements of Operations

(In thousands, except per share amounts)

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PEGASYSTEMS INC.

RECONCILIATION OF SELECTED GAAP TO NON-GAAP MEASURES (1)

($ in thousands, except per share data)

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PEGASYSTEMS INC.

RECONCILIATION OF SELECTED GAAP TO NON-GAAP MEASURES (1)

($ in thousands, except per share data)

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PEGASYSTEMS INC.

FOOTNOTES FOR RECONCILIATON OF

SELECTED GAAP MEASURES TO NON-GAAP MEASURES

Revenue: Business combination accounting rules require that we determine the fair value of the deferred revenue liability for contractual obligations assumed from Chordiant. In post-acquisition reporting periods, we recognize revenue for the fair value of these contracts, when all the revenue recognition criteria are satisfied, instead of the revenue that would have been recognized by Chordiant as an independent company. We add back the effect of the deferred revenue fair value adjustment in Non-GAAP revenue to reflect the full amount of these revenues to provide a more complete comparison with the revenue of peer companies.

Amortization of intangible assets: We have excluded the effect of amortization of intangible assets acquired from Chordiant from our Non-GAAP operating expenses and net earnings measures. Amortization of intangible assets is inconsistent in amount and frequency and is significantly affected by the timing and size of our acquisitions. Investors should note that the use of intangible assets contributed to our revenues earned during the periods presented and will contribute to our future period revenues as well. Amortization of intangible assets will recur in future periods.

Stock-based compensation expenses: We have excluded the effect of stock-based compensation expenses from our Non-GAAP operating expenses and net earnings measures. Although stock-based compensation is a key incentive offered to our employees, and we believe such compensation contributed to the revenues earned during the periods presented and also believe it will contribute to the generation of future period revenues, we continue to evaluate our business performance excluding stock-based compensation expense.

Acquisition-related costs and restructuring costs: We have excluded the effect of acquisition-related costs and restructuring costs from our Non-GAAP operating expenses and net earnings measures. We incurred direct and incremental costs associated with the Chordiant acquisition. These acquisition-related costs were primarily due diligence costs, advisory and legal transaction fees, and valuation and tax consulting fees. We have also incurred restructuring costs related to the integration of the acquisition, which we generally would not have otherwise incurred in the periods presented as a part of our continuing operations. Restructuring costs consist of employee severance and other exit costs. We believe it is useful for investors to understand the effects of these items on our total operating expenses.

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The GAAP provision for income taxes reflects an effective tax rate of 30.1% and 16.9% in the first six months of 2011 and 2010, respectively. The Non-GAAP provision for income taxes reflects an effective tax rate of 32.6% and 33.6% in the first six months of 2011 and 2010, respectively.

The difference between our GAAP and Non-GAAP effective tax rate in the second quarter and first six months of 2011 primarily relates to the impact of the change in the geographic mix of income and the related deduction for domestic production activities. The differences between our GAAP and non-GAAP tax rates in the second quarter and first six months of 2010 were due to the differences in allowable acquisition-related deductions for income tax purposes.

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Pegasystems Inc.

Unaudited Condensed Consolidated Balance Sheets

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Pegasystems Inc.

Unaudited Condensed Consolidated Statements of Cash Flows

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