Despite recent attention to death and dying, many questions remain about the diagnosis and treatment of depression in cancer patients. To provide a framework for effective treatment, this article distinguishes the following types of depression: (1) transient stress reactions, (2) major psychiatric disturbances requiring prompt attention, and (3) other depressive reactions. Depressions in the third general category, comprising the majority, are often mismanaged because of characterological, interpersonal, and organic factors receive insufficient attention. Understanding of such factors provides a basis for rational intervention with both patients and their families.