A notes survey was undertaken by a group of eight general practitioners in seven Southampton practices to study the mode of presentation and follow-up of the diabetic patients on the lists of 24 doctors. The 431 known diabetic patients were classified as non-insulin-dependent (67%), insulin-dependent (20%), or, if they had commenced their insulin more than a month after the diagnosis had been made, 'insulin-treated' (13%). This classification allowed characterization of the truly insulin-dependent and non-insulin-dependent patients.Non-insulin-dependent diabetics were older than insulin-dependent diabetics and had first presented at a greater age. Most patients in each treatment group presented with classical diabetic symptoms, diabetes-related infections, or recognized complications. The majority of these were diagnosed in general practice. However, over half of the asymptomatic non-insulin-dependent diabetic patients had been diagnosed by routine blood or urine testing in hospital. After 1979 fewer non-insulin-dependent diabetic patients were referred to hospital for follow-up at diagnosis than before 1975.Most non-insulin-treated diabetics were followed up in general practice whereas most patients treated with or dependent on insulin were followed up in hospital clinics. Twenty-two per cent of all patients received diabetic care from both their general practitioner and hospital outpatient departments but 20% received no regular diabetic follow-up at all. One year after the initial study, 4% of patients were still without regular review, and 27 more patients had been identified who would have qualified for the original audit.