A comprehensive approach to the supervision and training of teaching assistants (TAs) in the proficiency-based classroom might include a pre-service workshop, in-service methodology courses linked to appropriate teaching assignments, and systematic observations and evaluations of their performance as instructors. An intensive pre-service workshop can acquaint TAs with the mechanics of planning, instruction, and evaluation, familiarize them with university and department structure, and provide an overview of materials and the principles around which a proficiency-based classroom is organized. Substantial changes in the beginning level curriculum require methodology courses addressing features of the newly designed curriculum. A course for all first-year TAs meeting 2 hours weekly during the fall term and an additional 1-hour course each subsequent teaching term can provide the structure necessary for an organized presentation of basic teaching principles, course material previews, and guidance for a successful teaching and learning experience. Effective evaluation of TA performance in classroom teaching, methods course work, and team teaching is important. In the initial methodology course, TAs should develop a unit of materials, and evaluation can assess their effective classroom application. Classroom observation by program coordinator and other faculty, especially mentors, can be useful. An evaluation form and 32-item bibliography are provided. (MSE)