To determine resident and facility characteristics associated with do-not-resuscitate (DNR) orders and to test the effect of DNR orders on hospitalization of acutely ill nursing home (NH) residents with lower respiratory tract infections (LRIs). Prospective cohort. Thirty-six NHs (almost 4,000 residents) in central and eastern Missouri in the Missouri Lower Respiratory Infection study. NH residents with a LRI (n=1031). Data were obtained from new Minimum Data Set evaluations, resident examination, and chart review. Associations between resident, physician, and facility characteristics and the presence of a DNR order and hospitalization within 30 days from evaluation for an LRI were analyzed. Sixty percent of subjects had a DNR order, and 2% had a do-not-hospitalize order. Resident characteristics associated with a DNR order included older age, white race, having a surrogate decision-maker, NH residence for longer than 3 years, and more-impaired cognition. Residents with DNR orders were more likely to live in facilities with more licensed beds, a lower proportion of Medicaid recipients, and a higher prevalence of influenza vaccination. After controlling for potential confounders, residents with a DNR order before the acute illness episode were significantly less likely to be hospitalized (adjusted odds ratio=0.69, 95% confidence interval=0.49–0.97). DNR orders independently reduce the risk of hospitalization for LRI and may function as a marker for undocumented care limitations or as a mandate to limit care (unrelated to resuscitation) in NH residents with LRI. [ABSTRACT FROM AUTHOR]