A questionnaire to households in Oxfordshire identified 431 diabetic patients living in the area and 272 of them completed a questionnaire about their attitudes to and knowledge of diabetes, and were subsequently interviewed. Most did not regard diabetes as a serious disease and had little knowledge of possible complications. Patients found dietary compliance the most difficult part of their treatment. Among non-insulin treated patients there was a significant association between difficulty with diet and body mass index and glycosylated haemoglobin values. The results suggest that there is a need for more effective advice on diet and for better education of patients about the nature of diabetes and its complications.