Measures based on routinely collected data would be useful to examine the epidemiology of patient safety. Extending previous work, we established the face and consensual validity of twenty Patient Safety Indicators (PSIs). We generated a national profile of patient safety by applying these PSIs to the HCUP Nationwide Inpatient Sample. The incidence of most nonobstetric PSIs increased with age and was higher among African Americans than among whites. The adjusted incidence of most PSIs was highest at urban teaching hospitals. The PSIs may be used in AHRQ's National Quality Report, while providers may use them to screen for preventable complications, target opportunities for improvement, and benchmark performance.