The purpose of the study reported here was to determine whether improvement in medical knowledge affects medical students' interviewing skills in each, or any, of the four years of medical school. Nineteen first-year students, 21 second-year students, 18 third-year students, and 20 fourth-year students at the University of Iowa College of Medicine were randomly assigned to an experimental or a control group. The experimental group observed a 45-minute videotape lecture that discussed the practical issues of the diagnosis and management of children with meningomyelocele. All subjects in both groups then completed a multiple-choice examination on meningomyelocele. The interviews were videotaped and then blindly rated. The results of the ratings show that there was no group effect but there was a significant class difference in that the first-year class was less sophisticated than the three other classes. The results suggest that interview skills are not affected by increasing knowledge about medical conditions but do improve with training in interview skills.