In the study reported here the authors examined the relationships among 40 measures of undergraduate college and medical school performance and competence in 18 medical care tasks during the first year of residency. A rating form was developed for the study to assess residents' competency in the medical care tasks and was sent to the directors of the residency programs entered by the graduates of a medical school. Stepwise multiple regression procedures were used to analyze the relationship between these ratings of residency performance and the residents' premedical and medical school performance and to identify the best predictors of residency performance for the 1982 and 1984 classes. A Rasch model analysis of the residency performance ratings indicated the ease or difficulty of each of the 18 tasks. The results provide information that would allow medical educators to use premedical and medical school performance to predict residents' competencies. The task of "clinically evaluates research and clinical data" was the most difficult for the graduates; that is, they were rated lower on it than on any other task. Two groups of measures of undergraduate and medical school performance were significantly related to performance in the residency: the Part II examination of the National Board of Medical Examiners (particularly the scores on the obstetrics-gynecology, medicine, surgery, and pediatrics subtests and the overall score) and the clerkships (particularly the third-year medicine clerkship, the fourth-year medicine clerkship, and the surgery clerkship).