EXHIBIT 99.1

[ILLUMINA LOGO]                                                    Illumina, Inc
                                                                   NR200415

Contacts: Jay Flatley                         Timothy Kish
          President & CEO                     Chief Financial Officer
          1.858.202.4501                      1.858.202.4508
          jflatley@illumina.com               tkish@illumina.com

              ILLUMINA TO RAISE $30 MILLION IN REGISTERED OFFERING

SAN DIEGO, CALIFORNIA, May 11, 2004 -- Illumina, Inc. (NASDAQ: ILMN) announced
today that it has obtained commitments to purchase approximately $30.7 million
of its common stock in a registered direct offering. Under the terms of the
transaction, Illumina will sell approximately 4.5 million shares of its common
stock at $6.75 per share to a select group of institutional investors. The
closing of the offering is expected to take place on May 14, 2004, subject to
the satisfaction of customary closing conditions. All of the shares of common
stock are being offered by Illumina pursuant to an effective registration
statement previously filed with the Securities and Exchange Commission. SG Cowen
& Co., LLC acted as exclusive placement agent for the transaction.

This press release shall not constitute an offer to sell or the solicitation of
an offer to buy nor shall there be any sale of these securities in any state or
jurisdiction in which such offer, solicitation or sale would be unlawful prior
to registration or qualification under the securities laws of any such state or
jurisdiction. The shares of common stock may only be offered by means of a
prospectus. Copies of the final prospectus supplement and accompanying base
prospectus can be obtained from SG Cowen & Co., LLC at 1221 Avenue of the
Americas, New York, New York 10020, fax +1-212-278-7438.

ILLUMINA, INC.

Illumina (www.illumina.com) is developing next-generation tools that permit
large-scale analysis of genetic variation and function. The Company's
proprietary BeadArray(TM) technology -- now used in leading genomics centers
around the world -- provides the throughput, cost

effectiveness and flexibility to enable researchers in the life sciences and
pharmaceutical industries to analyze the billions of data points necessary to
extract valuable information that will help pave the way to personalized
medicine.

"Safe Harbor" Statement under the Private Securities Litigation Reform Act of
1995: this release may contain forward-looking statements that involve risks and
uncertainties. Among the important factors which could cause actual results to
differ materially from those in the forward-looking statements are Illumina's
ability to develop and obtain market acceptance for its Sentrix(R) BeadChip
whole genome microarrays, its ability to continue to improve its BeadArray and
Oligator(R) technologies, the Company's ability to reproducibly manufacture
Array Matrices and BeadChips and to reconfigure these platforms to other
geometries, the Company's ability to successfully build out international sales
and support organizations, the Company's ability to develop and deploy new
applications for its platform technology, and other factors detailed in the
Company's filings with the Securities and Exchange Commission including its
recent filings on Forms 10-K and 10-Q or in information disclosed in public
conference calls, the date and time of which are released beforehand. Illumina
disclaims any intent or obligation to update these forward-looking statements
beyond the date of this release.

                                      # # #