Because teaching hospitals face increasing pressure to justify their higher charges for clinical care, the quality of care in teaching and nonteaching hospitals is an important policy question. The most rigorous peer-reviewed studies published between 1985 and 2001 that assessed quality of care by hospital-teaching status in the United States provide moderately strong evidence of better quality and lower risk-adjusted mortality in major teaching hospitals for elderly patients with common conditions such as acute myocardial infarction, congestive heart failure, and pneumonia. A few studies, however, found nursing care, pediatric intensive care, and some surgical outcomes to be better in nonteaching hospitals. Some factors related to teaching status, such as organizational culture, staffing, technology, and volume, may lead to higher-quality care.