BACKGROUND: Medical students are generally young people, often away from home for the first time and undertaking a course in which they are learning to care for people at all stages of life, including those approaching death. Existing research indicates that their experiences of personal bereavement may have significant implications for their pastoral welfare and medical learning. No previous studies have tracked medical student experience of bereavement longitudinally and no recent data are available from the UK. AIMS: The study aims to identify medical students' experience of personal bereavement: the prevalence prior to and during the course and their relationship with those who died. METHOD: Paper and online questionnaire including questions about recent personal loss. SETTING / PARTICIPANTS: Four cohorts of core science and clinical medical students at the University of Cambridge, 1021 participants in total. RESULTS: Mean response rate was 65.2% for core science students and 72.8% for clinical students. On entry to the core science course, 23.1% of all students had experienced a loss at some point. Between 13.0% and 22.5% experienced bereavement during years 1 - 5 of the course: some (1.3% - 6.3%) experienced multiple or repeated losses. Close deaths reported were most commonly those of grandparents followed by friends. CONCLUSIONS: Medical students commonly experience close personal bereavement, both before and during their course. Educators need to be aware of the range of personal and educational implications of bereavement for medical students, and ensure that appropriate help is available. Further research could explore incidence of loss at other medical schools and investigate the impact and depth of experience of loss.