The aim of this study was to examine the factors influencing medical students' communication skills. The sample comprised all first-year clinical students. Thirty-two received teaching in communication skills during the year; the remaining 56 did not. Students' career preferences, attitudes towards communication skills and confidence in their ability to communicate with patients were assessed by questionnaire at the beginning and end of the year. At the end of the year each student was videotaped interviewing a simulated patient. Students' communication skills were assessed on the basis of this interview by raters using a standardized rating scale, and by patient questionnaires. While there was some evidence that brief communication skills training improved skills, sex of student was a more significant predictor of level of skill. Students who perceived communication skills as less relevant to medicine and those who were more confident about their own communication skills were more likely to prefer a career in hospital medicine. Students' judgements of their ability to communicate effectively were poor. In the main there was no relationship between confidence and level of skill: where they were related, the association was negative. The benefits from communication skills training might be enhanced by involving hospital doctors in the teaching, and providing students with detailed video feedback on their skills at the outset.