Despite the number of studies describing nurses' health-related behaviours, few have investigated psychosocial factors that influence these behaviours. Aim: To investigate the relationship of social support and locus of control to nurses' health-related behaviours. Design: A cross-sectional survey was used. Subjects: 114 nurses' attending tertiary level education courses in London and Essex. Measures: The Health and Behaviour Survey, The Six Item Social Support Questionnaire and the Multidimensional Health Locus of Control Scale. Results: Social support did not significantly relate to any health-related behaviour except eating fruit. Subjects high on internal locus of control also significantly reported eating less red meat, eating three meals per day on a regular basis and eating fewer between meal snacks. Conclusions: Locus of control is more strongly associated with United Kingdom nurses' health-related behaviours than social support. Given the empirical links between nurses' health-related behaviours and their tendency to counsel clients about health issues, attempts to improve nurses' internal locus of control may ultimately improve their health promotion role.