The importance of diagnosing depression and providing subsequent treatment to nursing home residents has been acknowledged and supported by the Centers for Medicare & Medicaid. The Mood section of the Minimum Data Set (MDS) 3.0 includes the Patient Health Questionnaire, Nine Questions (PHQ-9), in order to help identify depression. Depression is also associated with other chronic diagnoses such as Alzheimer’s disease, Parkinson’s disease, cancer, and arthritis. Substance use is often seen in the nursing home as a co-morbidity of depression for older adults. Depression and the diagnosis of depressed mood is a significant concern for social workers in long-term care. The social worker should be familiar with key signs and symptoms of depression, as well as the current modes of intervention, drug treatment, and psychotherapy.