Although malnutrition and wasting are known features of human immunodeficiency virus (HIV) infection, their incidence and possible association with immunologic impairment are largely unknown, as is the prognostic value of the nutritional state. Nutritional, clinical, and immunologic parameters were measured in 100 outpatients in different stages of HIV infection. In addition, 39 patients with AIDS were prospectively followed for a mean period of 343 (range, 53-650) days. Sixty-three percent of the patients showed evidence of malnutrition, 21% suffered from wasting. A reduced body cell mass and decreased serum albumin levels were observed in 32 and 14%, respectively, predominantly in more advanced disease stages. Fourteen of 39 AIDS patients died after a mean survival of 212 days. Survivors showed significantly larger initial body cell mass values and higher initial serum albumin levels compared with nonsurvivors, whereas CD4+ lymphocyte counts, disease complications, and medication were all similar in both groups. Kaplan-Meier analyses revealed a significantly prolonged survival in patients with a body cell mass > 30% of body weight or serum albumin levels exceeding 30 g/L. Factor analyses indicated that the parameters of nutritional state were independent from each other and from CD4+ lymphocyte counts. Malnutrition occurs frequently during HIV infection and increases with disease progress. It strongly predicts patient survival independent of CD4+ lymphocyte counts.