Stroke incidence was analysed in a Swedish cohort of male (n = 1428) and female (n = 1812) hypertensive patients in comparison with age- and sex-matched population controls (1:1) and with normotensive untreated subjects (1249 men and 1247 women). Mean follow-up was 8.3 years. Patients were aged 40-69 at the start of follow-up in 1977-1981. Relative risks (95% confidence interval [CI]) for stroke morbidity were 1.63 (1.16, 2.29) for men and 1.40 (0.94, 2.09) for women compared to population controls. Corresponding figures for stroke mortality were 1.96 (1.01-3.82) and 1.48 (0.71-3.06). Compared to the normotensive sample with adjustment for smoking and body mass index relative risks for stroke morbidity were 3.07 (1.96-4.80) for men and 2.56 (1.46-4.51) for women. The prognosis of treated hypertension with respect to stroke is better than anticipated from previous studies, a fact that should be considered when treatment guidelines are developed.