To correlate CD 4 counts with albuminuria and glomerular lesions in patients infected with human immunodeficiency virus (HIV), we studied 104 HIV positive patients (68 males, 36 females) of whom 100 patients were infected by heterosexual contact, 3 by transfusion, and 1 by i.v. drug abuse. We screened over nine months for albuminuria by urine dip stick method, and performed renal biopsy on patients with albuminuria 2+ or more. Histological examination was accomplished by light microscopy in all and by electron microscopy when it was feasible. Albuminuria was observed in 29 (27%) patients, and it revealed a significant negative correlation with CD4 count (p<0.01). Patients with CD4 cells <350 cells/mm(3) disclosed a 3.5 fold increased risk of albuminuria as compared with patients with CD4 >350 cells/mm(3). There was no significant correlation between proteinuria and the duration of infection from the time of diagnosis. Albuminuria also demonstrated a significant negative correlation with the levels of hemoglobin (p<0.05). In addition, low numbers of CD4 cells were associated with lower levels of hemoglobin (p<0.001). Only 10 patients received renal biopsies, and the results revealed HIV-associated nephropathy (HIVAN) in 7 (70%) patients, chronic tubulointerstitial nephritis in 1, membranous glomerulopathy in 1, and diffuse proliferative glomerulonephritis in 1. Acute renal failure was present in 5 patients, of whom four had a pre renal component and one had multiorgan dysfunction syndrome. We conclude that our study demonstrates that both proteinuria and HIVAN are common in HIV infected patients. Proteinuria has a negative correlation with the CD4 counts and hemoglobin levels.