Depression is a common, disabling, and costly condition encountered in older patients. Effective strategies for detection and treatment of late-life depression are summarized based on a case of a 69-year-old woman who struggled with prolonged depression. Clinicians should screen older patients for depression using a standard rating scale, initiate treatment such as antidepressant medications or evidence-based psychotherapy, and monitor depression symptoms. Patients who are not improving should be considered for psychiatric consultation and treatment changes including electroconvulsive therapy. Several changes in treatment approaches are usually needed before patients achieve complete remission. Maintenance treatment and relapse-prevention planning (summarization of early warning signs for depression, maintenance treatments such as medications, and other strategies to reduce the risk of relapse [eg, regular physical activity or pleasant activities]) can reduce the risk of relapse. Collaborative programs, in which primary care clinicians work closely with mental health specialists following a measurement-based treatment-to-target approach, are significantly more effective than typical primary care treatment.