The Bay Area Functional Performance Evaluation (BaFPE) was developed in 1977–1978 to meet the need for a reliable and valid instrument for assessing the general functional performance of patients treated in psychiatric occupational therapy. It consists of two subtests, the Task-Oriented Assessment and the Social Interaction Scale. These subtests evaluate two aspects of general functional performance—task-oriented and social behavior—that are important in assessing clients with emotional, cognitive, or behavioral deficits. This article traces the instrument’s standardization over a 10-year period of development and includes a discussion of its theoretical premises, its content, and the revisions to date. Research on the reliability and validity of the BaFPE is summarized.