The Food and Drug Administration (FDA or Agency) is announcing the availability of a guidance for industry entitled “Handling and Retention of BA and BE Testing Samples.” This guidance is intended to provide recommendations for applicants of new drug applications (NDAs) and abbreviated new drug applications (ANDAs), including supplemental applications, and contract research organizations (CROs), regarding the procedures for handling reserve samples from relevant bioavailability (BA) and bioequivalence (BE) studies, and recommendations regarding responsibilities of each party involved in the study pertaining to reserve samples. Additionally, this guidance describes the conditions under which the Agency generally does not intend to take enforcement action against an applicant or CRO that retains less than the quantity of reserve samples specified in the regulation.