The importance of differences in clinical characteristics between ethnic groups on operative mortality of coronary artery bypass grafting (CABG) has not been clarified. Data reporting to the California CABG outcomes reporting program is mandated under state law in California. Data from 121 hospitals in 2003 were analyzed, including clinical characteristics and predicted and observed operative mortalities in patients who underwent isolated CABG. In total 21,272 isolated CABGs were reported in 2003. Compared with Caucasians (n = 15,069), Hispanics (n = 2,561), Asians (n = 1,772), and African-Americans (n = 785) were younger, more likely to be women, and had more hypertension, diabetes, renal failure, and severe liver disease (all p values <0.05). Hispanics had more heart failure and Asians had a lower body mass index compared with Caucasians, whereas African-Americans had a higher body mass index and more peripheral artery disease and heart failure (all p values <0.05). Based on a multivariate model, the predicted operative mortality for Hispanics (3.2%), Asians (3.3%), and African-Americans (3.6%) was higher (all p values <0.001) than that of Caucasians (2.8%). However, observed operative mortality was similar across ethnic groups, although there was a trend toward higher mortality in Asians compared with Caucasians (3.5% vs 2.8%, p = 0.077). In conclusion, significant differences in risk profile for CABG exist across ethnicities. Although the predicted operative mortality for Hispanics, Asians, and African-Americans was significantly higher than that for Caucasians, there was no significant difference in the observed operative mortality.