Health hazards associated with the use of smokeless tobacco were evaluated in a cross-sectional study of 97,586 Swedish construction workers undergoing health examinations in 1971-74. All users of smokeless tobacco only (5014 subjects) and all exclusive smokers of > or = 15 cigarettes daily (8823 subjects) were compared with all non-users of any tobacco (23,885). Both smokeless tobacco users and smokers showed higher prevalences of circulatory and respiratory disorders. Hypertension was most common in smokeless tobacco users. In the 45- to 56-years age group, the odds ratio for a diastolic blood pressure of > 90 mmHg was 1.8 (95% CI, 1.5-2.1), and for a systolic blood pressure > 160 mmHg, 1.7 (95% CI, 1.3-2.1). Smokers showed the lowest prevalence of hypertension. Disability pensions due to cardiovascular disease were nearly 50% more frequent in both smokeless tobacco users and smokers. These findings indicate that an increased cardiovascular risk is also associated with the use of smokeless tobacco.