The Centers for Medicare and Medicaid Services publicly reports so-called process performance at all U.S. hospitals, such as whether certain recommended treatments are given to specific types of patients. We examined whether hospital performance on key process indicators improved during the three years since this reporting began. We also studied whether or not these changes improved patient outcomes or yielded other quality improvements, such as reduced hospital readmission rates. We found that, from 2004 to 2006, hospital process performance improved and was associated with better patient and quality outcomes. Most notably, for acute myocardial infarction, performance improvements were associated with declines in mortality rates, lengths-of-stay, and readmission rates. Although we cannot conclude that public reporting caused the improvement in processes or outcomes, these results are encouraging, since improving process performance may improve quality more broadly.