Seventy-nine of 673 patients attending a hypertensive outpatient clinic were classified as diabetics at the first examination. These patients were age- and sex-matched to two control groups: nondiabetic hypertensives and the background population. Nondiabetic hypertensive patients had a significantly poorer survival than expected during a 10-year observation period; the survival of diabetic hypertensives was even poorer, although not significantly. No sex difference was observed in the survival rates of hypertensive diabetics, neither was a difference seen between insulin-dependent and non-insulin-dependent patients. Acute myocardial infarction was the most frequent cause of death in both diabetic (40%) and nondiabetic (42%) hypertensive persons.