To estimate long-term efficacy of coronary bypass surgery, we examined our experience with 3155 patients observed over a 78-month period. Preoperative clinical profile, operative risk, and long-term symptomatic status and survival were compared in 2663 men and 492 women. To minimize influence of unequal baseline characteristics, surgical results were also compared in 412 pairs of men and women matched by computer for age, preoperative angina classification and number of diseased vessels. Operative mortality was not significantly different in matched patients. Women had smaller distal coronary arteries, more diabetes and hypertension, a higher rate of incomplete revascularization, and reduced graft patency compared with men. Cumulative survival for men and women was 92% at 42 months. At late follow-up, significantly more men were asymptomatic (70% vs 52%, p less than 0.001) and men achieved higher activity levels. We conclude that men have more symptomatic relief after coronary bypass surgery than women. A better-quality revascularization in men may be part of the reason for this outcome.