To assess the effects of bevantolol on stable angina pectoris of effort and its impact on metabolic risk factors, a comparison study of this beta 1-blocking agent and atenolol was undertaken in 40 subjects (mean age 51 years). After a 4-week, single-blind, placebo washout period, 12 men and 8 women were randomized to receive 150 mg of bevantolol twice daily and 12 men and 8 women to treatment with 100 mg of atenolol once daily in a parallel, double-blind, 12-week treatment phase. Patients were assessed at weeks 2, 6 and 12 after bicycle exercise until angina or ST-segment depression greater than or equal to 0.15 mV appeared. Concentrations of cholesterol lipoproteins and 3 prostaglandin metabolites were determined. One patient receiving bevantolol was withdrawn from the study because of insufficient efficacy and 2 receiving atenolol were withdrawn because of side effects. After 2 weeks of therapy, significant decreases were seen in both groups in the number of angina attacks, mean sitting heart rate, systolic and diastolic blood pressure, mean maximum heart rate during exercise and mean double-product of systolic blood pressure and heart rate at the end of exercise. There was a trend toward significance in the increase of mean duration of exercise and total work performed with both agents, although these values were not statistically significant. Both high density lipoproteins and the ratio of high density lipoproteins to low density lipoproteins increased in the bevantolol group and decreased in the atenolol group. These changes were statistically significant at week 6.(ABSTRACT TRUNCATED AT 250 WORDS)