Chronic diseases are usually the result of complex interactions between various lifestyle factors, physiological processes and societal factors. While some of these factors are not modifiable, modification of several of these factors have, to a large extent, demonstrated preventative properties against the development or further development of various chronic diseases. Health-related behaviours are modifiable factors. Behaviour plays an important role in both the development and the management of chronic diseases. One way of investigating this role is to evaluate the impact of health-related behaviours on health. Positive health-related behaviours include eating a healthy diet, regularly engaging in physical exercise, having regular screenings and checkups, not smoking, moderate alcohol use, getting vaccinations and seat belt use. Negative health-related behaviours include eating an unhealthy diet, leading a sedentary life style, not having regular screenings and checkups, smoking, excessive alcohol use and irresponsible driving. Various models of health-related behaviour use social cognitive factors as proximal determinants of health-related behaviours. A social cognitive factor that has received little attention in relation to health-related behaviour, that is sense of coherence (SOC), was used in this study. Although personality factors tend to be only distally associated with health-related behaviour, they do however seem to contribute to a better understanding of these behaviours. Trait emotional intelligence (EI) as a lower order personality trait was used in this study. The purpose of this study was to investigate the nature of the relationships between SOC, trait EI and health-related behaviours. A cross-sectional, correlational research design was used. Participants were selected based on convenient and easy access. Participants completed an online questionnaire that consisted of a health behaviour survey as well as the short form of the Orientation to Life Questionnaire and the Trait Emotional Intelligence Questionnaire. The health behaviour survey assessed some aspects of people's health-related behaviour, including diet, sleep and preventive behaviours, alcohol use, exercise and smoking. Health behaviour correlated significantly with both SOC and Trait EI. SOC and Trait EI were also significantly correlated. When controlling for a third variable, neither SOC nor trait EI correlated significantly with health behaviour. Although none of the predictors made significant contributions to the prediction of health behaviour, the basic regression model reached statistical significance. Trait EI made a significant contribution to the prediction of health behaviour in a more parsimonious regression model, which also reached statistical significance. / Dissertation (MA (Research Psychology))--University of Pretoria, 2008. / Psychology / unrestricted