The evaluation of a behavior and development training program that was integrated into a general pediatric training residency is reported. Thirty-two residents who participated in the program were evaluated over one year on measures designed to assess residents' opinions about the relevance of behavior and development concepts, residents' perceptions of their own competence in behavior and development knowledge and skills, supervisors' ratings of residents' general clinical performance, and residents' attitudes about 10 specific illnesses. Results suggest that residents perceive a high relevance for psychosocial concepts and an increasing competence with these concepts after training. Establishing rapport with patients emerged as an important variable in supervisors' ratings of resident performance and in residents' self-ratings of competence. Attitudes were initially negative toward the more behavioral and psychophysiological disease entities but showed some positive change over the year. These results and their implications are discussed.