The effects of an intensive feedback method on the teaching performance of ward attending physicians were evaluated. Sixty-four attending physicians were randomly assigned to one of four experimental groups: (1) intensive feedback, (2) videotape control, (3) questionnaire feedback, or (4) questionnaire control. The method was evaluated using the teachers' subjective assessments, ratings of videotapes of ward rounds, and trainee ratings. Seventy-five percent of the intensive feedback group rated their treatment definitely beneficial in contrast to less than 13 percent of teachers in other groups (p less than 0.001). The intensive feedback group received higher post-treatment videotape ratings than the videotape control group, both on ratings of specific categories of teacher behavior (p = 0.03) and on ratings of overall teaching performance (p = 0.08). More intensive feedback teachers (40 percent) than videotape control teachers (6 percent) improved their personally identified problem teaching behaviors (p less than 0.05). Trainee ratings showed no significant difference between study groups. It is concluded that attending physicians can improve their teaching performance. Intensive feedback is one possible method of achieving that goal.