As generic products become more available for the treatment of psychiatric disorders, clinicians must stay abreast of the U.S. Food and Drug Administration (FDA) requirements for the approval of generic drug products. The FDA declares that pharmaceutical equivalents only are therapeutically equivalent, and pharmacokinetic data are all that is usually required to determine therapeutic equivalence. The rationale behind the overall concept of bioequivalence is that if 2 pharmaceutical equivalents provide identical plasma concentration-time profiles in humans, there is no evidence to demonstrate that the 2 identical dosage forms will exhibit a difference in safety and efficacy. This article reviews current terminology used in abbreviated new drug applications for generic products, typical bioequivalence study designs, and FDA bioequivalence guidance for clozapine.