Normal pressure hydrocephalus (NPH) is a surgically correctable syndrome of progressive dementia, gait abnormalities, and urinary incontinence resulting from an occult hydrocephalus in association with normal cerebrospinal fluid pressure. Occurring most frequently in midlife and often idiopathic in origin, the early course of the illness may be characterized by symptoms of apathy, inattentiveness, agitation, and poverty of thought which mimic a depressive illness and may delay the recognition and treatment of the underlying structural defect. A review of the literature reveals that this association of depressive symptomatology and NPH has received little attention in the psychiatric literature, and the authors describe a case of NPH which presented as a severe, agitated depression. Clinical findings which suggest the presence of NPH are discussed, and the need to include NPH in the differential diagnosis of depression in the presenium is emphasized. The authors believe such diagnostic vigilance is necessary if the needless deterioration of potentially salvageable individuals is to be prevented.