The characteristics of Type 2 diabetes raise major questions on patients' behaviours and their determinants. The goal of this paper is to integrate recent empirical results of behavioural sciences and modern medical therapeutics in diabetes. We should consider all factors which may influence behavioural self-care while refer less to the normative logic of compliance. Behavioural sciences have demonstrated that various central factors should be considered to promote health behaviours in Type 2 diabetes: namely negative emotions, coping, personal models of illness and risk perception. All these concepts may constitute targets of practical interventions. These can either improve the quality of life, modify or individualise diabetes constraints, improve the focus of medical information given to the patient, favour a better acceptation of illness or a more active role towards diabetes. Self-monitoring of blood glucose and introduction of insulin may influence psychological determinants of self-care behaviours. These arguments are followed by a set of recommendations for the clinician and the researcher.