Most diabetic patients are elderly but their clinical characteristics remain poorly defined. A population survey identified 259 known diabetic patients aged 60 years or more giving a prevalence of 3% in this age group. A total of 193 patients (75%) were interviewed and examined, 155 (80%) of whom had been diagnosed at under 70 years of age. Forty-two patients (22%) were insulin-treated but clinical characteristics suggested that at least 95% of all elderly patients had Type 2 diabetes. Blood glucose control was poor with median HbA1 9.7% (range 4.9-17.1%, normal reference range 5.0-7.5%), and 55% were either overweight or obese. There was a high morbidity from diabetes and other conditions: the prevalence of hypertension (untreated blood pressure of 160/95 mmHg or more or antihypertensive medication) was 52%, of stroke 5%, of nephropathy (urinary albumin concentration greater than or equal to 300 mg l-1) 3%, of lower limb amputations 4%, and of foot ulcers 7%. The prevalence of symmetrically impaired distal vibration perception was 23%, and 54% of patients either needed or were receiving chiropody. The prevalence of a corrected distant visual acuity of 6/12 or worse was 32% and of retinopathy of any degree was 26%. There was extensive co-morbidity which was not confined to a single subgroup of patients.