The applications for sterility testing in the validation and routine control of sterilization of medical devices have changed dramatically over the years. As the definition of sterility assurance has evolved, so has the state of the science associated with product sterility testing. Historically, product sterility testing has been applied to such things as sterilization validation, sterilization lot release, packaging qualification, aseptic processing qualification, and determination of shelf life for the packaged medical device. In most of these cases, however, the results obtained from performing sterility testing on products do not provide the desired confirmation and assurance. Utilizing sterility testing on fully processed finished product is not appropriate for determination of sterilization process effectiveness, sterility assurance level, package integrity, or shelf life. The industry has developed more robust methods for validation of these applications to assure sterility and package performance. This article outlines the appropriate applications for sterility testing and highlight the applications currently in use that have significant limitations within the results and introduce undesirable risk to the validity of the data.