The problems of non-adherence with treatment in health care in general, and with medication adherence in particular, is an area with a voluminous and burgeoning literature. However, there appears to be no review of the literature on non-adherence with medications in organ transplant patients. This comprehensive review therefore considers literature on adherence in adult kidney, heart and liver transplantation. The particular problem of adherence in paediatric transplant patients is also addressed. This transplant research literature is then evaluated within the broader context of social science research on medication adherence. From the review it is apparent that there is an urgent need for research which examines the patient's beliefs about their illness and medicines. Such research is a precursor for rigorous nursing intervention studies which aim to promote adherence by being tailored to the patient's perceptions.