Abstract: A process challenge device tailored to mimic the resistance of a particular product to a particular biological inactivation, disinfection, or sterilization process, and used to challenge the process, thus providing a means to validate the efficacy of the process. The process challenge device is used by subjecting the device containing indicator organisms to an inactivation or sterilization process, and culturing any surviving indicator organisms as a means to assess the efficacy of procedures for the inactivation of microorganisms. The device uses a self-containing biological indicator (SCBI) with a biological indicator and media ampule located within a plastic vial. By altering the materials and/or configuration of the SCBI a wide range of resistances to sterilant gas processes may be achieved.