Patients undergoing isolated first-time elective coronary bypass surgery were classified according to their preoperative ejection fraction: group 1 comprised 131 patients with poor left ventricular function (ejection fraction < 40%); group 2 was 1,496 control patients. The mean number of distal anastomoses was not significantly different in the 2 groups, however, clamp time, pump time, and operative time were longer in group 1. Patient recovery was significantly slower in group 1. Morbidity (14.5% in group 1 versus 7.4% in group 2, p < 0.005) and mortality (2.3% versus 0.1%, p < 0.0001) were higher in group 1. During late follow-up, the 5-year survival rate (70.1% versus 90.5%) and 5-year event-free rate (65.6% versus 81.9%) were significantly inferior in group 1 compared to group 2. The results of bypass surgery in cases of decreased left ventricular function were poor, and such patients need to be carefully followed up.