We prospectively examined 1359 adult patients undergoing isolated coronary revascularization with the Pi-circuit technique, consisting of beating heart, aorta no-touch, use of composite grafts, and off-pump arterial revascularization. Patients were divided into two groups based on body weight; Group A consisting of 295 (21.7%) obese patients [body mass index (BMI) > or =30 kg/m(2)] and Group B of 1064 (79.3%) non-obese patients (BMI <30 kg/m(2)). Advanced age and emergency surgery favored the non-obese group [63.0+/-10.4 vs. 65.3+/-9.6 years (P<0.0005) and 10.2% vs. 17.1% (P=0.004), with an increase in the number of octogenarians among them (1.7% Group A vs. 5.4% in Group B, P=0.11)]. The use of double internal mammary arteries (90.5% in Group A vs. 86.9% in Group B, P=0.109), the mean number of distal anastomoses (2.8+/-0.9 in Group A vs. 2.7+/-0.9 in Group B, P=0.5) and the number of sequential anastomoses performed (28.1% in Group A vs. 31% in Group B, P=0.3) were similar. No difference in morbidity rates was detected. All cause in-hospital mortality was comparable. Survival was similar in both groups also. Obesity is not a risk factor for morbidity and mortality in this group of patients.