Little research exists on the outcome of smaller patients who undergo coronary artery bypass graft surgery. The purpose of this study was to evaluate the outcomes of cardiac surgery in smaller patients (males with body surface area of 1.6 square meters or less, and women with 1.5 meters or less). A consecutive series of 4,358 patients undergoing bypass surgery was evaluated. Of these, 246 (5.6%) were classified as small patients. Smaller patients were more likely to be women, older and of Asian ethnicity. They were less likely to have undergone a prior cardiac surgery. Smaller patients were less likely to receive an arterial conduit (74% versus 99%; p<0.00001). Rates of post-surgery complications differed between small and normal size patients, with smaller patients more likely to require prolonged ventilator support (p <0.05), more likely to have acute renal failure (p<0.0001), more transfusions and re-operation for bleeding (p<0.05), higher death rate (5.7% versus 2.6%; p<0.01) and longer length of hospital stay (11.4 versus 8.3 days; p<0.00001). In multivariate analyses evaluating factors related to death, emergent surgery, poor ejection fraction and older patient age were independently related to mortality. Small body surface area was not an independent predictor. The results of this study indicate that smaller patients do have poorer outcomes associated with coronary artery bypass surgery. However, 90% of the smaller patients did have an event-free surgery. Surgeons may need to monitor these patients more closely and anticipate the increased risk and cost that is associated with this group.