To determine whether cardioselective and nonselective β-blocking agents impair exercise training effects in patients with cardiovascular disease, 50 subjects were evaluated. All were in a 3-times-weekly medically supervised outpatient exercise program for 3 months or longer. Treadmill exercise tests were done initially and at 3-month intervals. Eight patients were receiving atenolol, 23 propranolol, 3 timolol, 6 metoprolol, and 8 nadolol and 1 patient receiving timolol changed to atenolol and 1 receiving nadolol changed to propranolol. Treadmill test duration increased significantly (p <0.05), from 7.5 ± 2.5 to 9.9 ± 2.3 minutes, with exercise training. In 35 of the 50 subjects heart rate at rest decreased significantly (p <0.05) from 67.5 ± 11.7 to 60.4 ± 10.5 beats/min. The other 15 subjects were excluded from heart rate analysis because β blockade was begun 1 to 2 weeks after the initial exercise test. It is concluded that exercise training effects (increase in exercise test duration and decrease in resting heart rate) can be achieved in patients with cardiovascular disease in the presence of both cardioselective and nonselective β-blocking agents.