When California passed a law in 1999 establishing minimum nurse-to-patient staffing ratios for hospitals, it was feared that hospitals might respond by disproportionately hiring lower-skill licensed vocational nurses. This article examines nurse staffing ratios for California hospitals for the period 1997-2008. It compares staffing levels to those in similar hospitals in the United States. We found that California's mandate did not reduce the nurse workforce skill level as feared. Instead, California hospitals on average followed the trend of hospitals nationally by increasing their nursing skill mix, and they primarily used more highly skilled registered nurses to meet the staffing mandate. In addition, we found that the staffing mandate resulted in roughly an additional half-hour of nursing per adjusted patient day beyond what would have been expected in the absence of the policy. Policy makers in other states can look to California's experience when considering similar approaches to improving patient care.