Abstract Background: Off-pump coronary artery bypass surgery has emerged as an alternative technique to traditional onpump surgery. The aim of this randomized study was to compare perioperative morbidity and mortality and intraoperative and short-term graft patency in off-pump and on-pump coronary artery bypass grafting. Methods: One hundred twenty patients were randomized for coronary revascularization with or without cardiopulmonary bypass. In all patients grafts and anastomoses were monitored with transit time Doppler ultrasonography and angiography. Angiography was repeated 3 months after the procedure in 115 of the patients. Results: Angiography 3 months postoperatively revealed that internal mammary artery patency was 98% in both groups. Vein graft patency was 83% in the off-pump group and 91% in the on-pump group, a difference that was not statistically significant. One perioperative death was recorded in each group. Two strokes were recorded in the on-pump group, none in the off-pump group. Conclusion: In this prospective, controlled study, perioperative and short-term outcome of off-pump coronary surgery equaled that of on-pump surgery.