PROSPECTUS SUMMARY

The following is a summary of what we believe to be the most important aspects of our business and the offering of shares of our common stock under this prospectus. We urge you to read this entire prospectus, including the more detailed consolidated financial statements, notes to the consolidated financial statements and other information incorporated by reference from our other filings with the SEC. Investing in our common stock involves risks. Therefore, carefully consider the information provided under the heading “Risk Factors” beginning on page 5.

About Orchid Biosciences

Overview

We are engaged in the development and delivery of genetic testing, or genotyping, services that generate information related to disease susceptibility and genetic uniqueness, or the genetic variability that distinguishes one organism from another. This information is generated from the analysis of DNA.

DNA based genotyping, or analyzing DNA by identifying a single difference in the nucleotide base of DNA for comparing genetic variability between people, has become a widely used standard technology for the establishment of paternity and forensic identification. Genotyping has also been adapted for food safety and selected animal testing applications (which we refer to as public health testing). Our business includes public health testing services, such as animal susceptibility testing to breed sheep resistant to scrapie disease. Our services are used extensively in each of these applications and we expect their uses to increase. We also expect our services to be used in new genotyping markets, such as food traceability; or being able to identify the source of a meat or plant product based on genotyping.

We conduct paternity genotyping determinations for government agencies and private individuals in North America, and provide forensic DNA testing for primarily government agencies in the United States (US). We also have operations located in the United Kingdom (UK), which provide paternity, forensics and animal susceptibility testing.

History

We incorporated as a Delaware corporation and began operations in 1995. In the first three years of business we were primarily focusing on developing our Microfluidics technologies for applications in high throughput production of small molecules under collaborative research programs with SmithKline Beecham and Sarnoff Corporation. Microfluidics is primarily the movement and pumping of very minute fluids, which was essential to the mechanization of laboratory research. In 1998, we made a fundamental shift in our business focus to apply our technology to determine genetic variability and differences, including single nucleotide polymorphisms, or SNPs, and perform genotyping services. At this time, we acquired substantially all of the assets of Molecular Tool, Inc. a wholly owned subsidiary of GeneScreen, Inc. (GeneScreen). Molecular Tool’s proprietary primer extension technology, which enabled us to determine a single base pair variation within DNA, for genotyping SNPs matched our existing Microfluidics technologies and allowed us to focus our business on genetic diversity. We also developed instruments and kits that could be used for genotyping to be performed independently by third parties. Although we do not currently utilize our Microfluidic technology, we do license this technology to others for their use. In December 1999, we acquired GeneScreen, a provider of services to determine identity based on genomic technology, or identity genomics. During 2000, our collaborative research programs with SmithKline Beecham and Sarnoff Corporation expired by their terms, and we amended our relationship with Sarnoff Corporation which provided us with a fully paid license to the technology that was the subject of the Sarnoff collaboration, which was primarily related to Microfluidics. In 2001, we acquired two other identity genomics businesses: Cellmark Diagnostic (Cellmark), a business division of AstraZeneca, a provider of DNA laboratory testing in the UK and a supplier of genotyping products for human inherited disease diagnosis; and Lifecodes

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Corporation (Lifecodes), a national provider of identity genomics testing for forensics and paternity with multiple laboratories in the US, and a provider of human leukocyte antigens, or HLA, genotyping products and services for transplantation compatibility testing.

In early 2002, we began the process of realigning our business into strategic units for marketing purposes. As a result of this realignment, we organized our business into four business units consisting of Orchid Identity Genomics, Orchid Diagnostics, Orchid GeneShield, and Orchid Life Sciences. Additionally, our international operations, which encompassed all of our business units, were managed under a regional business unit, Orchid Europe. The business units operated in the following areas:

At the end of 2002 and throughout 2003, we sharpened our business focus and moved away from the multiple business units established in early 2002. We concentrated our efforts on genotyping services directed towards forensics, paternity and public health applications, which were the basis of the Orchid Identity Genomics business unit. As part of this strategy, we have discontinued the operations of the Orchid Life Sciences and Orchid Diagnostics business units and have scaled back significantly our pharmacogenomics efforts formerly conducted by the Orchid GeneShield business unit.

After we exited these businesses, we determined that we operate our business under one segment, the development and delivery of genetic testing, services that generate information related to genetic susceptibility and uniqueness, or the genetic variability that distinguishes one organism from another. During the quarters ended March 31, June 30 and September 30 of 2003, we reported Orchid public health as a separate segment, however, upon further analysis, we concluded public health should be included with our Identity Genomics business unit and we now operate under one reporting segment.

We have never been profitable, and as of December 31, 2003, we had an accumulated deficit of $287.5 million. However, we expect that we have enough cash on hand to fund current and future operations at least through 2004, at which time we expect to be cash flow self sufficient.

We were incorporated in Delaware in 1995. Our principal executive offices are located at 4390 US Route One, Princeton, New Jersey, 08540. Our telephone number is (609) 750-2200 and our web site address is www.orchid.com. We make available free of charge through the Investors section of our web site our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, current reports on Form 8-K and all amendments to those reports as soon as reasonably practicable after such material is electronically filed with or furnished to the Securities and Exchange Commission (the “SEC”). We include our web site address in this Amendment No. 1 to Form S-3 as an inactive textual reference only.

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The Orchid logo, Genescreen, Lifecodes and Cellmark are trademarks, registered trademarks, service marks or registered service marks of Orchid BioSciences, Inc. Unless the context otherwise requires, the terms “Orchid BioSciences,” “we,” “us” and “our” refer to Orchid BioSciences, Inc. and its subsidiaries.

Reverse Stock Split

On January 9, 2004, we announced an intention to seek stockholder approval of a proposal to implement a reverse stock split ranging from 1-for-3 shares to 1-for-7 shares. On February 27, 2004, we obtained stockholder approval to implement the reverse stock split. On March 25, 2004, we announced that our Board of Directors had approved a reverse stock split ratio of 1-for-5. We began trading on a reverse split basis on March 31, 2004. All amounts presented in our 2003 Annual Report on Form 10-K incorporated herein by reference have not been adjusted to reflect the reverse stock split. However, all amounts presented in this prospectus have been adjusted to reflect the reverse stock split.