In this paper we review studies of depression in patients with HIV/AIDS. Methodological issues of importance in understanding and evaluating depression in this patient population are described, and methodological variations between studies, particularly in reference to methods of case detection, diagnostic criteria used and characteristics of the populations studied, are identified. The findings reported in the current literature in general are contrary to what would be expected from an examination of the significant biological and psychosocial stresses of individuals with HIV, and are inconsistent with those of other life-threatening illnesses and CNS diseases. Clear conclusions regarding the prevalence of depression and its effect in patients with HIV/AIDS cannot yet be made.