The computer code that comprises UCSF Chimera and ChimeraX is protected by copyrights held by The Regents of the University of California ("The Regents"). Futhermore, UCSF Chimera and ChimeraX are licensed for non-commercial use at no cost by The Regents. COMMERCIAL USE OF UCSF CHIMERA AND CHIMERAX ARE COVERED BY A SEPARATE WRITTEN LICENSE AGREEMENT(S); please contact us for details. You must agree to the terms and conditions of use as specified in the UCSF Chimera license agreement before you will be permitted to download Chimera.

Chimera extension developers please note: The purpose of the Ownership and Assignment of Copyright section of the license agreement is to protect The Regents' exclusive rights as copyright holder in the existing code and derived works based on this code. It does not cover original code developed by others. Extensions to Chimera and ChimeraX that are not modifications, improvements, or derivatives of code copyrighted by The Regents are considered the property of their authors. (The programming examples we provide are explicitly NOT copyrighted!)

Commercial use of Chimera is covered by a separate, written license agreement. Commercial licensing costs are tier-based, depending on the number of users. Please contact us if you are interested in using Chimera for commercial purposes.