Exhibit 99.1

				Repligen Corporation
				41 Seyon Street
				Building #1, Suite 100
				Waltham, Massachusetts 02453

Repligen Reports Second Quarter 2016 Financial Results

- Exceptional second quarter puts Company on track for 21%+ revenue growth for 2016-

WALTHAM, MA – August 4, 2016 – Repligen Corporation (NASDAQ:RGEN), a life sciences company focused on bioprocessing technology leadership, today reported financial results for the second quarter ended June 30, 2016. Detailed in this press release are the Company’s performance highlights for the period, followed by updated financial guidance for the year 2016 and access information for today’s webcast and conference call.

Tony J. Hunt, President and Chief Executive Officer said, “We continue to be encouraged by the strength in demand for our bioprocessing products and the positive trends in our industry. We achieved record revenue of $29.2 million in the second quarter of 2016, an increase of 36% from the same period in 2015, driven by strong demand for OPUS^® purification columns, XCell™ ATF systems and growth factors. It was also an important quarter in terms of executing on our long-term growth strategy. In April, we acquired Atoll GmBH (“Atoll”), and in May we completed a $115 million convertible debt financing to support ongoing acquisition initiatives as well as internal investments to expand our global infrastructure.”

Financial Highlights for the Second Quarter of 2016

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Financial Highlights for the First Half of 2016

On a GAAP basis, revenue for the first half of 2016 was $54.3 million, an increase of 28% compared to the first half of 2015. Gross margin was 56.3% for the first half of 2016, reflecting gross profit of $30.6 million, an increase of 19% year-over-year. Income from operations increased to $9.3 million for the first half of 2016, compared to $8.6 million for the 2015 period. Net income for the first half of 2016 was $5.5 million compared to $6.5 million for the first half of 2015. EPS for the first half of 2016 was $0.16 per fully diluted share compared to $0.19 for the first half of 2015.

On a non-GAAP basis, adjusted income from operations was $13.1 million for the first half of 2016, a year-over-year increase of 24%. Adjusted net income was $9.6 million for the first half of 2016, a year-over-year increase of 14%. Adjusted EPS for the first half of 2016 increased to $0.28 from $0.25 for the first half of 2015.

Our non-GAAP adjusted operating income, adjusted net income and adjusted EPS for the first half of 2016 exclude the impact of Atoll acquisition and integration expenses of $1.1 million that we record in SG&A and Refine contingent consideration expense of $2.6 million. Our non-GAAP adjusted net income and adjusted EPS results for the first half of 2016 also exclude the non-cash interest expense of $0.4 million. Our non-GAAP results for the first half of 2015 exclude the impact of Refine contingent consideration expense of $1.9 million.

Financial Guidance for 2016

Based on our current projections, including taking into account our acquisition of Atoll in April 2016 and our convertible debt financing in May 2016, we are updating our guidance for the year 2016. This guidance is based on expectations for our existing business and does not include the financial impact of potential additional Refine contingent consideration, potential new acquisitions or future fluctuations in foreign currency exchange rates.

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Conference Call

Repligen will host a conference call and webcast today, August 4, 2016, at 8:30 a.m. EDT, to discuss second quarter 2016 financial results and corporate developments. The conference call will be accessible by dialing toll-free (844) 835-7432 for domestic callers or (404) 537-3372 for international callers. Dial-in participants must provide the passcode 53964467. In addition, a webcast will be accessible via the Investor Relations section of the Company’s website. Both the conference call and webcast will be archived for a period of time following the live event. The replay dial-in numbers are (855) 859-2056 for domestic callers and (404) 537-3406 for international callers. Replay listeners must provide the passcode 53964467.

Non-GAAP Measures of Financial Performance

To supplement our financial statements, which are presented on the basis of U.S. generally accepted accounting principles (GAAP), the following non-GAAP measures of financial performance are included in this release: revenue growth rate at constant currency, adjusted income from operations, earnings before interest, taxes, depreciation and amortization (EBITDA), adjusted EBITDA, adjusted net income and adjusted earnings per diluted share (EPS). The Company provides revenue growth rates in constant currency to exclude the impact of foreign currency translation in order to facilitate a comparison of its current revenue performance to its past revenue performance. To calculate revenue growth rates in constant currency, the Company converts actual net sales from local currency to U.S. dollars using constant

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foreign currency exchange rates in the current and prior period. The Company’s non-GAAP measures exclude the impact of contingent consideration related to the Company’s June 2014 asset purchase agreement with Refine Technology, the impact of contingent consideration and acquisition costs related to the Company’s April 2016 acquisition of Atoll GmBH, and the impact of non-cash, and in the case of EBITDA, cash interest expense related to the Company’s May 2016 convertible debt issuance. These costs are excluded because management believes that such expenses do not have a direct correlation to future business operations, nor do the resulting charges recorded accurately reflect the performance of our ongoing operations for the period in which such charges are recorded. Refine contingent consideration is triggered by the achievement of annual ATF System sales milestones through the end of the year 2016, and Atoll-related contingent consideration is tied to sales of the acquired chromatography product through the end of the year 2016.

A reconciliation of GAAP to adjusted non-GAAP financial measures is included as an attachment to this press release. When analyzing the Company’s operating performance investors should not consider non-GAAP measures as substitutable for the comparable financial measures prepared in accordance with GAAP.

About Repligen Corporation

Repligen Corporation (NASDAQ:RGEN) is a bioprocessing company focused on the development, manufacture and commercialization of highly innovative products used to manufacture biologic drugs. Our bioprocessing products are sold to major life sciences companies, biopharmaceutical development companies and contract manufacturing organizations worldwide. We are the leading manufacturer of Protein A affinity ligands, a critical component of Protein A resins that are used to separate and purify monoclonal antibody-based therapeutics. In upstream processes, our XCell™ ATF systems and cell culture growth factors are used to accelerate and increase product yield during the fermentation stage of biologic drug manufacturing. In downstream processes, we developed and market our innovative line of OPUS^® chromatography columns that we deliver pre-packed with our customers’ choice of resin for their bench-scale through clinical production-scale purification needs. Repligen’s corporate headquarters are in Waltham, MA (USA) and our manufacturing facilities are located in Waltham, MA, Lund, Sweden and Weingarten, Germany.

The following constitutes a “Safe Harbor” statement under the Private Securities Litigation Reform Act of 1995: This press release contains forward-looking statements, which are made pursuant to the safe harbor provisions of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Investors are cautioned that statements in this press release which are not strictly historical statements, constitute forward-looking statements, including, without limitation, express or implied statements or guidance regarding current or future financial performance and position, including cash and investment position, expected revenue growth from acquisitions, the potential impairment of future earnings, management’s strategy, plans and objectives for future operations or acquisitions, product development and sales, selling, general and administrative expenditures, intellectual property, development and manufacturing plans, availability of materials and product and adequacy of capital resources and financing plans constitute forward-looking statements identified by words like “believe,” “expect,” “may,” “will,” “should,” “seek,” “anticipate,” or “could” and similar expressions. Such forward-looking statements are subject to a number of risks and uncertainties that could cause actual results to differ materially from those anticipated, including, without limitation, risks associated with: our ability to successfully grow our bioprocessing business, including as a result of acquisition, commercialization or partnership opportunities; our ability to successfully integrate the Atoll business; our ability to develop and commercialize products and the market acceptance of our products; reduced demand for our products that adversely impacts our future revenues, cash flows, results of operations and financial condition; our ability to compete with larger, better financed bioprocessing, pharmaceutical and biotechnology companies; our compliance with all Food and Drug Administration and EMEA regulations; our volatile stock price; and other risks detailed in Repligen’s most recent Annual Report on Form 10-K on file with the Securities and Exchange Commission and the other reports that Repligen periodically files with the

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Securities and Exchange Commission. Actual results may differ materially from those Repligen contemplated by these forward-looking statements. These forward looking statements reflect management’s current views and Repligen does not undertake to update any of these forward-looking statements to reflect a change in its views or events or circumstances that occur after the date hereof except as required by law.

Repligen Contact:

Sondra S. Newman

Senior Director Investor Relations

(781) 419-1881

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REPLIGEN CORPORATION

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME

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REPLIGEN CORPORATION

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REPLIGEN CORPORATION

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