Objective: Depression among older home care patients is prevalent but undertreated. The purpose of this study was to investigate the ability of home health nurses to correctly identify depression among older patients and to describe nurse and patient characteristics associated with more accurate assessment of depression. Methods: Forty-two nurses were surveyed about the presence of depressive symptoms among patients who had been evaluated independently for depressive disorders by research staff using the Structured Clinical Interview for Axis I DSM-IV Disorders. A sample of newly admitted home health care patients who were aged 65 years or older was randomly selected for this evaluation on a weekly basis from December 1997 to December 1999. Results: Of 403 patients who were evaluated, 97 (24 percent) were found to have either major depression (64 patients) or minor depression (33 patients). The nurses correctly identified depression among 44 of the 97 patients who were depressed (sensitivity of 45.4) and 230 of the 306 patients who were not depressed (specificity of 75.2). The kappa coefficient measuring overall agreement between the nurses' assessment and the diagnosis of depression was .19. Nurses who had more geriatric nursing experience were more likely to correctly identify depression. Conclusions: Home health nurses have difficulty making accurate assessments of depression among older home care patients. Inaccuracy in assessment of depression by home health nurses is a significant barrier to treatment in this elderly homebound population.