Stroke incidence, case fatality and mortality in diabetic patients were compared to non-diabetic subjects in a 35-74-year-old population in northern Sweden (target population 241,000). During an 8-year period, 1,544 stroke events in diabetic patients and 4,826 events in non-diabetic subjects were recorded. The crude incidence of stroke was 1,000 per 100,000 in the diabetic men vs 247 in the non-diabetic men (relative risk 4.1; 95% confidence interval 3.2-5.2). Among diabetic women, the crude incidence was 757 per 100,000 and 152 in non-diabetic women (relative risk 5.8; 95% confidence interval 3.7-6.9). The 28-day case fatality among men was similar in the diabetic and non-diabetic stroke patients (18.6 vs 17.1%; p = 0.311), but significantly higher in diabetic women compared with non-diabetic women (22.2 vs 17.9%; p = 0.02). When compared with the non-diabetic population, the overall mortality from stroke in the diabetic population (first and recurrent) was 4.4-times higher in male and 5.1-times higher in the female patients. Hypertension, atrial fibrillation, heart failure or myocardial infarction were all significantly more common in diabetic than in non-diabetic stroke patients. The population attributable risk, a crude estimate of all strokes ascribed to diabetes mellitus, was 18% in men and 22% in women. In Sweden, about 50 strokes are annually directly attributed to diabetes in a population of 100,000 in this age group.