Eleven percent (N = 25) of 232 dementia patients seen in an active geropsychiatry service also met criteria for major depression. Ten patients with dementia/depression were prospectively compared with 10 nondepressed demented and 33 nondemented depressed patients on pretreatment and posttreatment ratings of depression and copgnition/memory. Seventy percent (N = 7) of the dementia/depression group and 73% (N = 24) of the depression-only group responded to antidepressant therapy. Signs and symptoms of depression complicating dementia were similar to depressive phenomena in the depression-only group. Depression with dementia appeared to lower performance on cognitive tests. Following treatment, althoug cognitive impairment remained in the demented range, test performance improved.