Objective: To evaluate systematic management of hypertensive patients with regard to cardiovascular morbidity and mortality. Design: In a matched cohort study (1978-1993) the number of cardiovascular events among hypertensive patients under continuous systematic management four general practices was compared with those occurring among hypertensive patients from eight 'usual care' general practices. Subjects: The source population consisted of employees of a major electronic company in Eindhoven with hypertension as determined at an occupational health examination. The index group (n = 120) consisted of employees who were participating in the systematic management program in four practices. A reference group of 120 patients was selected from hypertensive employees who were registered in eight 'usual care' practices by matching for age, gender, fasting blood glucose, and frequency of occupational health examinations. The total cohort consisted primarily of males (78%), whose ages ranged from 50 to 65 years. Main outcome measures: Risk difference (RD) per 1000 patient years regarding left ventricular hypertrophy, heart failure, angina pectoris, myocardial infarction, transient ischaemic attack, stroke, peripheral arterial disease, nephropathy, retinopathy, cardiac death, death due to stroke, and non-cardiovascular death was determined. In addition to morbidity and mortality, systematic hypertension management was evaluated with regard to cardiovascular risk factors throughout a period of maximally 12 successive years (1978-1989). Morbidity and mortality data were derived from general practice records and archives; data on risk factors were assessed at bi-annual occupational health examinations. Results: The total follow-up duration amounted to 2628 patient years. The mean follow-up duration in the index group was 10.8, in the reference group 11.1 years. As compared to the 'usual care' reference group, the index group showed less left ventricular hypertrophy (RD 8.2, 95% CI 1.4-15.0), less angina pectoris (RD 9.7, 95% CI 2.0-17.4) and less peripheral arterial disease (RD 3.7, 95% CI 0.5-7.1). The difference in mean decrease in blood pressure during follow up was 11.3 mmHg systolic and 5.9 mmHg diastolic in favour of the index group. No significant differences between the index and the reference groups were found with regard to the changes in other risk factors. Conclusion: In our study systematic management of hypertensive patients aged 50 to 65 in general practice was associated with a statistically significant, and clinically relevant decrease in cardiovascular morbidity and blood pressure. Although causality cannot be determined from this non-randomized cohort study, the findings do support the view that systematic management of hypertensive patients in general practice is valuable.