OBJECTIVES: Depression remains underrecognized and undertreated in older people. We estimated the prevalence of depression in older nursing home (NH) residents and described its pharmacological management. DESIGN: Cross-sectional study. SETTING: Residents in 1,492 NHs in five states (Kansas, Maine, Mississippi, New York, South Dakota). PARTICIPANTS: Forty-two thousand nine hundred one residents aged 65 and older with depression documented as an active clinical condition on the Minimum Data Set (MDS) assessment. MEASUREMENTS: Data were from the Systematic Assessment of Geriatric drug use via Epidemiology database. We grouped antidepressant medications by class: tricyclic antidepressants (TCAs), tetracyclics, selective serotonin re-uptake inhibitors (SSRIs), monoamine oxidase inhibitors, and others. Logistic regression models revealed predictors of receipt of any antidepressant and, among those treated, predictors of receipt of an SSRI. RESULTS: Eleven percent of the residents were identified as depressed on the MDS. Of these, 55% received antidepressant therapy. Of depressed residents receiving antidepressant therapy, 32% received doses less than the manufacturers' recommended minimum effective dose for treating depression, with residents on TCAs more likely to receive less than the recommended dose for treating depression. The oldest-old (greater than or equal to85 years) (odds ratio (OR) = 0.93, 95% confidence interval (CI) = 0.88-0.98), black residents (OR = 0.83, 95% Cl = 0.75-0.92), and those with severe cognitive impairment (OR = 0.69, 95% CI = 0.64-0.75) were the least likely to receive an antidepressant. In those treated, cardiovascular diseases were associated with an increased likelihood of SSRI use. Despite control for comorbid conditions, women were less likely than men to receive an SSRI (OR = 0.77, 95% CI = 0.72-0.82). CONCLUSIONS: Although depression is a treatable illness, the majority of NTH residents may be inadequately treated.