Exhibit 99.1

FOR IMMEDIATE RELEASE

Deltek Reports Product Revenue of $28.4 Million, Up 15% from 2011

Product Bookings increase 23% to $33.3 million

Q2 Non-GAAP Operating Income increases 48%

HERNDON, Va. – July 31, 2012 – Deltek, Inc. (Nasdaq: PROJ), the leading global provider of enterprise software and information solutions for professional services firms and government contractors, today announced financial results for the quarter ended June 30, 2012.

Q2 product revenue was $28.4 million, up 15% from Q2 2011. Product bookings in Q2 were $33.3 million, a 23% increase from the same period in the prior year.

Q2 maintenance revenue was $41.5 million, an increase of 5% from $39.4 million in 2011. Consulting services and other revenue was $16 million, compared to $23.8 million in 2011. In Q2 2011, consulting services and other revenue included $3.5 million of revenue from our Insight user conference. In 2012, our Insight user conference is scheduled in Q4. Total revenue for Q2 2012 was $86 million, compared to $88 million in 2011. Our 2011 total revenue also included $3.5 million in Insight user conference revenue.

Non-GAAP operating income for the second quarter of 2012 increased 48% to $16.9 million, compared to $11.4 million in Q2 2011. Q2 Non-GAAP operating margin increased to 20%, compared to 13% in Q2 2011.

Non-GAAP net income for the second quarter of 2012 was $9.5 million, compared to $5.2 million in 2011, an increase of 84%. Q2 Non-GAAP EPS was $0.14, an increase of $0.06 from Q2 2011.

Q2 GAAP operating income was $8.8 million, an increase of $10.7 million when compared to a GAAP operating loss of $1.9 million in the prior year. Q2 GAAP operating margin was 10%, compared to a GAAP operating loss of 2% in Q2 2011.

Q2 GAAP net income improved by $7.2 million, from a $3 million loss in Q2 2011 to $4.2 million of net income in Q2 2012. Q2 GAAP EPS was $0.06, compared to a loss of $0.05 per diluted share in Q2 2011.

“Q2 was another excellent quarter for Deltek, highlighted by very strong product bookings and product revenue, continuing growth in our recurring revenue streams and significantly increasing margins,” said Kevin Parker, president and CEO of Deltek. “Our GovCon product bookings and revenue grew by more than 20%, with contractors both large and small investing in Deltek’s solutions. Our Information Solutions business delivered rapid growth in Q2 with bookings increasing 35% over the prior year. We also continued our expansion in the broader Professional Services market, with key wins in the accounting, legal and marketing communications industries.

“Our success through the first half of 2012 clearly demonstrates that Deltek’s specialized project-focused software and information solutions are resonating very well in the market. The growing demand for our new solutions including project manufacturing and our cloud-based offerings clearly indicates the significant new opportunities we have in front of us. Our overall pipeline is very active and expanding with a number of large opportunities on the horizon, and we expect strong growth through the rest of the year.”

Comparison of GAAP and Non-GAAP Measurements

Non-GAAP operating income and margin exclude the pre-tax impact of stock-based compensation, amortization of acquired intangible assets, purchase accounting impacts relating to acquisitions, acquisition-related costs, and restructuring charges. Non-GAAP net income excludes the same items on a net-of-tax basis.

A reconciliation of GAAP to non-GAAP financial measures is provided in the tables at the end of this press release.

Product Bookings

Product bookings consist of the aggregate contract value of the Company’s products sold during the quarter through its various licensing models including perpetual, term and subscription.

Recent Highlights

Conference Call Information

Deltek will host a conference call at 5:00 p.m. Eastern Time today to discuss the Company’s second quarter 2012 results. The dial-in number for the conference call is 1-877-381-6419 in

North America and 1-706-643-9496 outside North America (passcode: 95046832). The conference call also can be accessed through the Investor Relations section of Deltek’s website (http://investor.deltek.com). Those unable to participate in the live call may hear a replay through August 7, 2012 by dialing 1-855-859-2056 in North America and 1-404-537-3406 outside North America (passcode: 95046832). The replay also will be available through August 30, 2012 on Deltek’s website.

About Deltek

Deltek (Nasdaq: PROJ) is the leading global provider of enterprise software and information solutions for professional services firms and government contractors. For decades, we have delivered actionable insight that empowers our customers to unlock their business potential. 15,000 organizations and 2 million users in over 80 countries around the world rely on Deltek to research and identify opportunities, win new business, optimize resources, streamline operations, and deliver more profitable projects. Deltek – Know more. Do more.^® www.deltek.com

Use of Non-GAAP Financial Measures

This press release and the related conference call described above contain certain non-GAAP financial measures, including non-GAAP net income, non-GAAP operating income and margin, adjusted EBITDA, and non-GAAP revenue. The Company defines non-GAAP net income as GAAP net income (loss) before the net-of-tax impact of stock-based compensation, amortization of acquired intangible assets, purchase accounting impacts relating to acquisitions, acquisition-related costs, and restructuring charges. Non-GAAP operating income and margin is defined as GAAP operating income (loss) before the pre-tax impact of stock-based compensation, amortization of acquired intangible assets, purchase accounting impacts relating to acquisitions, acquisition-related costs, and restructuring charges. Adjusted EBITDA is defined as GAAP net income (loss) before interest expense (net of interest income), provision for income taxes, depreciation, stock-based compensation, amortization, purchase accounting impacts relating to acquisitions, acquisition-related costs, and restructuring charges. Non-GAAP revenue is defined as revenue before the net impact of acquisition-related fair value adjustments to deferred revenue.

The Company believes that the presentation of these measures provides useful information to its investors and lenders because these measures allow for more accurate comparisons of results from period-to-period, enhance the overall understanding of the Company’s performance and provide greater insight into the prospects for the Company’s ongoing business operations. Moreover, the Company also believes it is appropriate to exclude costs associated with restructuring charges because these charges are excluded from management’s assessment of the Company’s operating performance and are not related to the Company’s ongoing business operations. In addition, the Company excludes the items from EBITDA described above in its calculations to determine compliance with its debt covenants and to assess its ability to borrow additional funds to finance or expand its operations.

The Company believes that by reporting these measures, it provides insight and consistency in its financial reporting and presents a basis for comparison of its business operations between current, past and future periods. In addition, the measures provide a basis for the Company to compare its financial results to those of other comparable publicly traded companies and are used by its management team to plan and forecast its business.

Non-GAAP financial measures should not be considered as a substitute for, or superior to, measures of financial performance which are prepared in accordance with U.S. GAAP and may be different from non-GAAP financial measures used by other companies. Investors are encouraged to review the reconciliations of our GAAP to non-GAAP net income, operating income and margin, adjusted EBITDA and revenue, which are set forth below.

Forward-Looking Statements

This press release and related conference call contain forward-looking statements that involve substantial risks and uncertainties. You can identify forward-looking statements by words such as “anticipate,” “believe,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “should,” “would” or similar words. You should consider these statements carefully because they discuss our plans, targets, strategies, prospects and expectations concerning our business, operating results, financial condition and other similar matters. We believe that it is important to communicate our future expectations to our investors. There will be events in the future, however, that we are not able to predict accurately or control. Our actual results may differ materially from the expectations we describe in our forward-looking statements. Factors or events that could cause our actual results to materially differ may emerge from time to time, and it is not possible for us to accurately predict all of them. Before you invest in our common stock, you should be aware that the occurrence of any such event or of any of the additional events described as risk factors in the Company’s filings with the Securities and Exchange Commission could have a material adverse effect on our business, results of operation and financial position. Any forward-looking statement made by us in this press release or related conference call speaks only as of the date on which we make it. We undertake no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

DELTEK, INC.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands, except per share data)

(unaudited)

DELTEK, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(in thousands, except share data)

(unaudited)

DELTEK, INC.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

(unaudited)

DELTEK, INC.

RECONCILIATION OF GAAP NET INCOME (LOSS) TO NON-GAAP NET INCOME

(in thousands, except per share data)

(unaudited)

RECONCILIATION OF GAAP OPERATING INCOME (LOSS) AND OPERATING MARGIN (DEFICIT) TO NON-GAAP OPERATING INCOME AND OPERATING MARGIN

(in thousands)

(unaudited)

RECONCILIATION OF GAAP NET INCOME (LOSS) TO ADJUSTED EBITDA

(in thousands)

(unaudited)

REVENUES

(in thousands)

(unaudited)

STOCK-BASED COMPENSATION EXPENSE

(in thousands)

(unaudited)

AMORTIZATION OF ACQUIRED INTANGIBLE ASSETS

(in thousands)

(unaudited)

AMORTIZATION AND DEPRECIATION EXPENSES

(in thousands)

(unaudited)