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                                                                   EXHIBIT 10.27

                            NEGATIVE PLEDGE AGREEMENT

         This Negative Pledge Agreement is made as of December 29, 2003, by and
between ATHEROGENICS, INC. ("Borrower") and SILICON VALLEY BANK ("Bank").

         In connection with, among other documents, the Loan and Security
Agreement dated March 6, 2002 between Borrower and Bank and the Third
Modification Agreement being concurrently executed herewith between Borrower and
Bank (the "Loan Documents"), Borrower agrees as follows:

         1.       Borrower shall not sell, transfer, assign, mortgage, pledge,
                  lease, grant a security interest in, or encumber, or enter
                  into any agreement, document, instrument or other arrangement
                  (except with or in favor of Bank and except as permitted by
                  the Loan Documents) with any Person which directly or
                  indirectly prohibits or has the effect of prohibiting Borrower
                  from selling, transferring, assigning, mortgaging, pledging,
                  leasing, granting a security interest in or upon, or
                  encumbering any of Borrower's (i) Intellectual Property (as
                  defined in the Loan and Security Agreement) and (ii) cash,
                  deposit accounts and securities accounts maintained with Bank
                  and/or any of Bank's affiliates, including, without
                  limitation, the following:

                  (a)      Any and all copyright rights, copyright applications,
                           copyright registrations and like protections in each
                           work or authorship and derivative work thereof,
                           whether published or unpublished and whether or not
                           the same also constitutes a trade secret, now or
                           hereafter existing, created, acquired or held;

                  (b)      All mask works or similar rights available for the
                           protection of semiconductor chips, now owned or
                           hereafter acquired;

                  (c)      Any and all trade secrets, and any and all
                           intellectual property rights in computer software and
                           computer software products now or hereafter existing,
                           created, acquired or held;

                  (d)      Any and all design rights which may be available to
                           Borrower now or hereafter existing, created, acquired
                           or held;

                  (e)      All Patents, patent applications and like protections
                           including, without limitation, improvements,
                           divisions, continuations, renewals, reissues,
                           extensions and continuations-in-part of the same,
                           including without limitation the patents and patent
                           applications;

                  (f)      Any trademark and servicemark rights, whether
                           registered or not, applications to register and
                           registrations of the same and like protections, and
                           the entire goodwill of the business of Borrower
                           connected with and symbolized by such trademarks;

                  (g)      Any and all claims for damages by way of past,
                           present and future infringements of any of the rights
                           included above, with the right, but not the
                           obligation, to sue for and collect such damages for
                           said use or infringement of the intellectual property
                           rights identified above;

                  (h)      All licenses or other rights to use any of the
                           Copyrights, Patents or Trademarks, and all license
                           fees and royalties arising from such use to the
                           extent permitted by such license or rights;

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                  (i)      All amendments, extensions, renewals and extensions
                           of any of the Copyrights, Trademarks or Patents;

                  (j)      Any and all cash, deposit accounts, securities,
                           securities entitlements, securities accounts, and
                           certificates of deposit pledged to or maintained with
                           Bank and/or any of Bank's affiliates.

                  (k)      All proceeds and products of the foregoing, including
                           without limitation all payments under insurance or
                           any indemnity or warranty payable in respect of any
                           of the foregoing.

         2.       It shall be an event of default under the Loan Documents
                  between Borrower and Bank if there is a breach of any term of
                  this Negative Pledge Agreement.

         3.       Borrower hereby authorizes Bank to file or amend any Uniform
                  Commercial Code financing statement in order to give public
                  notice of the terms of this Negative Pledge Agreement.

         4.       Capitalized terms used but not otherwise defined herein shall
                  have the same meaning as in the Loan Documents.

         5.       This Negative Pledge Agreement replaces and supercedes the
                  existing Negative Pledge Agreement dated as of March 6, 2002
                  by and between Borrower and Bank.

                                          BORROWER:

                                          ATHEROGENICS, INC.

                                          By: /s/MARK P. COLONNESE
                                              ----------------------------------
                                          Name:  Mark P. Colonnese
                                          Title: Chief Financial Officer

                                          BANK:

                                          SILICON VALLEY BANK

                                          By: /s/ANGELA HART
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                                          Name:  Angela Hart
                                          Title: Vice President