This paper presents a model for training graduate students to teach, and reports the experiences and outcomes of an intitial application of the approach. The application took place with a large undergraduate class in introductory psychology with a professor in charge, assisted by five beginning graduate teaching assistants. The course met twice weekly, once as a large group for lecture by the professor, and once in small groups led by the teaching assistants. The assistants were given autonomy in determining the directions of their seminars, but were closely monitored. Most of the assistants lacked confidence in their teaching competencies and had difficulty asserting their authority. There was considerable competition among them for approval from the supervisor. It was difficult for them to cope with negative attitudes from their students, and they found it hard to evaluate them objectively. The following recommendations are made for improving such a training program: (1) clear definition of the roles for the teaching assistants in their sections; (2) increased training in the course's subject matter prior to assisting in it; (3) clear preview of what will take place in the supervision sessions; (4) a more active role for supervisors as they observe assistants' class performance; and (5) clear guidelines to teaching assistants regarding basic instructional procedures. (JD)