An overview is presented of a performance-based assessment system, Teacher Performance Assessment Instruments (TPAI), developed by the Teacher Assessment Project at the University of Georgia to measure competencies of beginning teachers for initial professional certification. To clearly separate the preparation and certification functions within the state, the Georgia Department of Education created a Performance Based Certification (PBC) model for prospective professional teachers. Beginning in the fall of 1980, the subject field proficiency of all beginning teachers will be demonstrated through the use of a criterion-referenced knowledge test. When employed as a beginning teacher, the TPAI will be used for assessment. Five performance assessment instruments have been developed: (1) Teaching Plans and Materials; (2) Classroom Procedures; (3) Interpersonal Skills; (4) Professional Standards; and (5) Student Perceptions. These instruments are admininstered through observation and/or interview with the teacher being assessed. Georgia is the first state to commit itself to the implementation of a PBC model for beginning teachers. Some developmental procedures and problems, measurement problems, performance standards, and the legality of performance assessment systems for certification are discussed. Other associated issues are presented in consideration of many southeastern states presently contemplating similar PBC models. (Author/GSK)