The efficacy and tolerability of amlodipine 2.5-10 mg once daily was compared with nadolol 40-160 mg once daily in a long-term double-blind parallel-group study in patients with stable exertional angina pectoris. A total of 80 patients were randomized to receive amlodipine or nadolol for 26 weeks after a 2-week single-blind placebo run-in period. The effects of amlodipine and nadolol on total exercise time were minimal and not significantly different. However, amlodipine produced a slightly but not significantly greater increase in time to onset of angina than nadolol (+21% amlodipine; +8% nadolol). No significant differences were noted between amlodipine and nadolol on ST-segment depression, angina attack rate, or nitroglycerin consumption. A slightly greater improvement was attained after amlodipine on patient and investigator assessments of treatments. A statistically significant difference (p < 0.0001) was found between treatments on the effects on myocardial oxygen requirements (as assessed by the rate pressure product). Nadolol produced a reduction of 29% compared with a slight reduction of 4% with amlodipine. Fewer side effects were reported with amlodipine (43%) than with nadolol (83%) (p < 0.0001), resulting in discontinuation of therapy in three amlodipine and four nadolol patients. Long-term treatment with amlodipine and nadolol produced comparable effects in patients with angina pectoris, with fewer side effects being reported after treatment with amlodipine.