CAMBRIDGE, Mass.–Helicos BioSciences Corporation (NASDAQ: HLCS), today announced the sale of a Helicos® Genetic Analysis System to a collaborative Dutch research group led by the Leiden University Medical Center (LUMC), further including the medical centers of Amsterdam (AMC) Groningen (UMCG) and Rotterdam (Erasmus MC) and funded by a grant from NWO, the Netherlands Organization of Scientific Research. The system will be installed at the Leiden Genome Technology Center (LGTC), headed by Professor Johan den Dunnen, a leader in the fields of genomic research and technology.

“We are very proud to have LUMC as a customer. They have a strong tradition of adopting breakthrough technologies and have seen the unique benefits of single molecule analysis first-hand.” stated Ron Lowy, Helicos Chief Executive Officer.

The relationship between the medical center and Helicos began with a collaboration in which researchers at the LUMC’s Forensic Laboratory (FLDO) provided the company with ancient human DNA samples for analysis using Helicos’ revolutionary True Single Molecule Sequencing (tSMS)™ technology. Unlike alternative, amplification-based, next-generation sequencing technologies, Helicos’ tSMS approach provided informative human sequences from these ancient remains, demonstrating the technology’s unique ability to analyze highly degraded and compromised DNA samples. The project was led by Professor Peter de Knijff and graduate student Eveline Altena. The resulting data were reported at various conferences in September and October of 2009, including at the American Society of Human Genetics Conference in Honolulu. The data are being prepared for publication.

“Based on our initial results with another technology, we were not expecting to get much information from these highly degraded samples. Helicos was able to provide us with a surprisingly high proportion of human sequence information from these historical human remains, allowing us to determine their ancestry and relatedness for the first time. This was beyond our greatest expectations.” said LGTC’s Johan den Dunnen.

The Helicos Genetic Analysis System is the world’s first and only commercially available, single molecule sequencing technology, and enables scientists to conduct revolutionary studies in the fields of genome biology, cancer research, common diseases, and microbiology without DNA ligation or amplification. Genetic analysis with Helicos’ technology eliminates the biases, complexity and errors introduced by DNA amplification, requires minute amounts of starting material, is amenable to the analysis of degraded nucleic acids, and provides the most direct and accurate view of biological samples.

About Helicos BioSciences:

Helicos BioSciences is a life science company focused on innovative genetic analysis technologies for the research, drug discovery, and diagnostic markets. Helicos’ proprietary True Single Molecule Sequencing, tSMS(TM), technology allows direct measurement of billions of strands of DNA enabling scientists to perform experiments and ask questions never before possible. Helicos is a recipient of the $1,000 genome grant and committed to providing scientists the tools to unlock the era of genomic medicine. The company’s corporate headquarters are located at One Kendall Square, Building 700, Cambridge, MA 02139, and its telephone number is (617) 264-1800. For more information, please visit www.helicosbio.com.

About LUMC:

Leiden University Medical Centre (LUMC) is a center for medical innovation, committed to the advancement of health care through research and innovation. Its focus is on translational research to accelerate the trajectory from the laboratory findings to clinical application and into the market place. As academic medical center it provides patient care and medical education. LUMC performs 15,600 daytime treatments and 20,000 hospital admissions yearly, and employs 7,000 people. For more information see www.lumc.nl.

Certain statements made in this press release that are not based on historical information are forward-looking statements which are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. This press release contains express or implied forward-looking statements relating to, among other things, the Company’s expectations regarding future sales and adoption of the Helicos® Genetic Analysis System and technology, and management’s plans, objectives and strategies. These statements are neither promises nor guarantees, but are subject to a variety of risks and uncertainties, many of which are beyond Helicos’ control, which could cause actual results to differ materially from those contemplated in these forward-looking statements. In particular, the risks and uncertainties include, among other things, our ability to successfully complete and/or scale the manufacturing and commercialization process for the Helicos Genetic Analysis System; our history of operating losses and ability to achieve profitability; our ability to sustain and scale our manufacturing capabilities; the research and development spending levels of academic, clinical and governmental research institutions and pharmaceutical, biotechnology and agriculture companies who may purchase our Helicos® Genetic Analysis System; our reliance on third-party suppliers; competition; changing technology and customer requirements; our ability to operate in an emerging market; market acceptance of our technology; the length of our sales and implementation cycles; our dependence on large contracts for the sale and implementation of our Helicos Genetic Analysis System; failure of our technology and products; our ability to maintain customer relationships and contracts; ethical, legal and social concerns surrounding the use of genetic information; our ability to retain our personnel and hire additional skilled personnel; our ability to manage our growth while operating with limited resources; our ability to control our operating expenses; general economic and business conditions; our ability to obtain capital when desired on favorable terms; and the volatility of the market price of our common stock. Existing and prospective investors are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. Helicos undertakes no obligation to update or revise the information contained in this press release, whether as a result of new information, future events or circumstances or otherwise. For additional disclosure regarding these and other risks faced by Helicos, see the disclosure contained in Helicos’ public filings with the Securities and Exchange Commission.