To determine changes in hospital mortality that occurred in association with the dissemination of data by a regional initiative to profile hospital performance, we conducted a retrospective cohort study of patients admitted before and subsequent to dissemination of comparative data in 1992. The analysis included 101,060 consecutive eligible discharges from 30 hospitals in Northeast Ohio with eight diagnoses: acute myocardial infarction, congestive heart failure (CHF), obstructive airway disease, gastrointestinal hemorrhage, pneumonia, stroke, coronary artery bypass surgery, and lower bowel resection. Baseline (1991, N = 35,629) mortality rates were compared to rates during three subsequent periods (July-December 1992, N = 20,392; January-June 1993, N = 23,070; and July-December 1993, N = 21,969). Mortality rates were risk-adjusted using validated multivariable models based on data abstracted from patient's medical records. For all conditions, risk-adjusted mortality declined from a baseline rate of 7.5% to rates of 6.8%, 6.8%, and 6.5%, respectively, during the three subsequent periods. Using weighted linear regression analysis to estimate trends across periods, declines in mortality rates were significant for CHF (0.50% per period; P = 0.002) and pneumonia (0.38% per period; P = 0.03). We conclude that hospital mortality declined in association with the dissemination of comparative data. Although changes in hospital care were not directly examined, the results suggest that initiatives to examine provider performance may have a beneficial impact on quality of care.