Clinical results of coronary artery bypass surgery have been evaluated analyzing operative mortality and its related risk factors. Four hundred and thirty seven consecutive patients undergoing coronary artery bypass surgery between January 1979, and December 1983, form the clinical material of this study. The gender of patients was male in 89% of the cases, the age ranged from 34 to 78 years with a mean of 54.8 +/- 8.2 (SD); patients with combined surgical procedures were excluded. The operative mortality was 5.49% (24 patients); no significant difference was found between years of the observation period. Death was due to cardiac causes in 75% of cases. Statistical analysis carried on 14 clinical, angiographic and surgical variables identified as significant risk factors of operative mortality age (p = 0.002) and cross-clamp time (p = 0.016). Both of these increased their weight when entered in a stepwise logistic regression. The EF also showed a value close to statistical significance (p = 0.06).