Background California launched the coronary artery bypass graft surgery (CABG) Outcomes Reporting Program in 2003 for all nonfederal hospitals performing this procedure. The program provides annual public reports of risk-adjusted operative mortality rates by hospital and surgeon. However, the impact of this program on operative mortality and access to surgery for high-risk patients has not been clarified. Methods The cohort consisted of all isolated CABG cases from the California CABG Outcomes Reporting Program database for 2003 and 2006. We applied the same multivariable logistic risk adjustment model to each year to compute predicted and risk-adjusted operative mortality for isolated CABG by hospital and surgeons. Changes in surgical volume and observed, predicted, and risk-adjusted operative mortality were compared by quintiles of patients based on the predicted risk and among hospitals and surgeons between 2003 and 2006. Results Total volume of isolated CABG decreased by 26.5% from 2003 (N = 21,276) to 2006 (N = 15,647). The reduction in CABG volume between 2003 and 2006 was universal among hospitals and surgeons regardless of their performance status in 2003. The change in patient case mix for a majority of hospitals and surgeons was insignificant, and overall patient risk was stable (statewide predicted operative mortality rate for 2003, 3.06%; 95% confidence interval, 2.98 to 3.13; and for 2006, 3.05%; 95% confidence interval, 2.97 to 3.14). Yet, the statewide observed mortality declined from 2.90% in 2003 to 2.22% in 2006 ( p = 0.0001). Overall, the empiric odds ratio of operative death for 2006 patients was 24% lower than for 2003 patients. In 2006, patients with the highest predicted operative mortality risk (4th and 5th quintiles) had 35% and 26% lower odds of operative mortality, respectively, when compared with patients from 2003. Conclusions Although total CABG volume decreased from 2003 to 2006 by almost 27%, patient case mix for most hospitals and surgeons was unchanged. Despite similar patient characteristics, the operative mortality for patients in the highest risk group was 26% lower in 2006 than in 2003. We found no evidence of decreased access to CABG for high-risk patients in California during the period of public reporting of isolated CABG outcomes.