OBJECTIVES: To evidence the respective advantages and drawbacks of minimal invasive-thoracotomy (MIDCAB) and off-pump sternotomy (OPCAB) coronary bypass techniques. METHODS: The perioperative and mid-term (3 months) results of the first 31 MIDCABs and 39 OPCABs performed by a single experienced coronary surgeon (F.S.) were compared. Differences were assessed by two-tailed chi-square or unpaired t-test, and significance assumed for P-values < or =0.05. RESULTS: Groups were widely comparable. There were no in-hospital deaths nor permanent neurologic events. OPCAB patients received more anastomoses (mean 1.09/patient vs. 1.89/patient, P<0.001) during a shorter coronary occlusion period (26.1+/-8 vs. 16.6+/-4.5min, P<0.001), whilst immediate extubation prevailed in MIDCABs (22/31 vs. 17/39, P<0.05). Significant complications occurred in seven MIDCABs vs. none in OPCABs (P<0.01). Other in-hospital parameters were similar. Controls at 3 months evidenced more residual discomfort among MIDCAB patients (14/30 vs. 7/39, P<0.05). CONCLUSIONS: Differences in early complication rates may be due to a learning effect. However, OPCAB allows us to implant more grafts and is more comfortable for both patient and surgeon. These advantages may well counterbalance the cosmetic benefits of MIDCAB procedures.