Beneficial health behaviours, such as exercise and healthy dietary intake, contribute to the improvement of public health. Levels of these behaviours are well below targets set by authorities. The purpose of the present study was to examine the personality and coping determinants of these health behaviours and evaluate their role as coping mechanisms. As high stress predicts poor health behaviours, it was hypothesized that successful coping would be associated with more beneficial health behaviours. Participants were 29 undergraduate psychology students who completed a week long food diary and a battery of self-reports including, the COPE inventory, a Five-Factor Model questionnaire and the Godin Leisure Time Exercise Questionnaire. Between-subjects analysis revealed that coping generally predicted health behaviours in the hypothesized way, however subscales within coping styles were differentially related to health behaviours. Within-subjects analysis revealed personality relations with health behaviours and stress. Personality partially predicted relations between physical and mental health, with the most consistent finding in results being the relationship with Conscientiousness and successful coping mechanisms and beneficial health behaviours. The dimension of Openness to Experience was found to play a more prominent role than in previous research. Exercise Coping was associated with beneficial mental and physical health, but results for Eating Unhealthily were less reliable. The three-factor higher order structure of coping adopted by this study limited findings.