The objective of this study is to investigate whether hospitals known to be good places to practice nursing have lower Medicare mortality than hospitals that are otherwise similar with respect to a variety of non-nursing organizational characteristics. Research to date on determinants of hospital mortality has not focused on the organization of nursing. We capitalize on the existence of a set of studies of 39 hospitals that, for reasons other than patient outcomes, have been singled out as hospitals known for good nursing care. We match these "magnet" hospitals with 195 control hospitals, selected from all nonmagnet U.S. hospitals with over 100 Medicare discharges, using a multivariate matched sampling procedure that controls for hospital characteristics. Medicare mortality rates of magnet versus control hospitals are compared using variance components models, which pool information on the five matches per magnet hospital, and adjust for differences in patient composition as measured by predicted mortality. The magnet hospitals' observed mortality rates are 7.7% lower (9 fewer deaths per 1,000 Medicare discharges) than the matched control hospitals (P = .011). After adjusting for differences in predicted mortality, the magnet hospitals have a 4.6% lower mortality rate (P = .026 [95% confidence interval 0.9 to 9.4 fewer deaths per 1,000]). The same factors that lead hospitals to be identified as effective from the standpoint of the organization of nursing care are associated with lower mortality among Medicare patients.