To determine the prevalence rates of major depressive disorder and of depressive symptoms and their relationship to mortality in nursing homes, research psychiatrists examined 454 consecutive new admissions and followed them up longitudinally for 1 year. Major depressive disorder occurred in 12.6% and 18.1% had depressive symptoms; the majority of cases were unrecognized by nursing home physicians and were untreated. Major depressive disorder, but not depressive symptoms, was a risk factor for mortality over 1 year independent of selected physical health measures and increased the likelihood of death by 59%. Because depression is a prevalent and treatable condition associated with increased mortality, recognition and treatment in nursing homes is imperative.