Research in the last 25 years has shown that diabetic patients' adhesion to medical advice is a multi-factor phenomenon. Most recent research has focused on a patient-centred approach, on the representations that the patient has with respect to medicine, health and disease (with particular regard to the perceived self-efficiency in managing the disease, trust in conventional medicine, treatment, drugs, etc) and on the level of agreement between the patient's representations and those of the health care provider. These representations can potentially act as barriers/facilitators on patients' adhesion to treatment; the best adherence can only be obtained if the real needs of the patient are met, matching therapy with his/her representations and expectations, and acknowledging the constraints that everyday life puts on the individual. The indication is therefore to avoid exclusively considering the physical burdens of the disease, while ignoring the personal and social significance of the experience that the patient is having. It will take time for this to become routine in health care, since it requires a complex change from a traditional, bio-medical approach to an integrated bio-psycho-social approach. The aim of this review is to show how those disease representations of diabetes, and the treatment having considerable impact on patients' adhesion, are being considered in recent literature, and how this nonetheless still constitutes a little explored aspect in medical consultation and research.