We assessed the feasibility of systematic off-pump coronary artery bypass (OPCAB) and identified risk factors for on-pump conversion.Between July 1, 2002 and December 31, 2003, OPCAB was attempted for all patients who required isolated coronary artery bypass in our institution. The perioperative results of patients were prospectively entered into a structured database, the results were analyzed to identify the risks of requirement of cardiopulmonary bypass.OPCAB was performed in all but 4 patients, giving an OPCAB success rate of 98.3% (229/233). The reason for cardiopulmonary bypass was hemodynamic instability occurring during reoperative surgery in 3, and cardiogenic shock in 1. The isolated risk factor for on-pump conversion was reoperation (relative risk 11.6). Mean number of distal anastomoses performed under OPCAB was 3.7+/-1.2, and the complete revascularization rate was 92.1% (211/229). There was one hospital death (0.4%). During a mean follow-up period of 1.0+/-0.4 years, two patients developed angina, which were treated with catheter intervention; otherwise, there was no death, or other cardiac events observed.Systematic OPCAB was feasible except in patients undergoing reoperative surgery or patients with on-going deep cardiogenic shock. Systematic OPCAB provided successful complete revascularization and its short term results were acceptable.