Gentle alternatives to existing sterilization methods are called for by rapid advances in biomedical technologies. Supercritical fluid technologies have found applications in a wide range of areas and have been explored for use in the inactivation of medical contaminants. In particular, supercritical CO(2) is appealing for sterilization due to the ease at which the supercritical state is attained, the non-reactive nature, and the ability to readily penetrate substrates. However, rapid inactivation of bacterial endospores has proven a barrier to the use of this technology for effective terminal sterilization. We report the development of a supercritical CO(2) based sterilization process capable of achieving rapid inactivation of bacterial endospores while in terminal packaging. Moreover, this process is gentle; as the morphology, ultrastructure, and protein profiles of inactivated microbes are maintained. These properties of the sterilization process suit it for possible use on a wide range of biomedical products including: materials derived from animal tissues, protein based therapies, and other sensitive medical products requiring gentle terminal sterilization.