Extensive attention has been paid over the past three decades to the stressors involved in training in the health professions. Although empirical studies have identified demographic subgroups of students most likely to become distressed during training, less research has been carried out to evaluate the impact of students' personality characteristics on their adjustment. Severe perfectionism is one such personality trait that has been shown to increase the risk for anxiety and depressive disorders in other populations. Another set of personality traits linked to increased psychological problems has been labelled the 'impostor phenomenon', which occurs when high achieving individuals chronically question their abilities and fear that others will discover them to be intellectual frauds. Both perfectionism and the impostor phenomenon would seem to be pertinent factors in the adjustment of health professional students; however, these character traits have not been empirically examined in this population. In the present study psychological distress, perfectionism and impostor feelings were assessed in 477 medical, dental, nursing and pharmacy students. Consistent with previous reports, the results showed that a higher than expected percentage of students (27.5%) were currently experiencing psychiatric levels of distress. Strong associations were found between current psychological distress, perfectionism and impostor feelings within each programme and these character traits were stronger predictors of psychological adjustment than most of the demographic variables associated previously with distress in health professional students. Implications for future research, limitations of this study and clinical recommendations are discussed.