In 3 patients with Salmonella-Schistosoma mansoni association and clinical evidence of renal lesions, a percutaneous renal biopsy was performed. Renal function, assessed by endogenous creatinine clearance, was abnormal in 2 cases and serum levels of complement were decreased in all cases. Immune complex glomerulonephritis, evidenced by the presence of immunoglobulin and complement in the glomeruli was demonstrated in all cases. S. dublin and S. typhimurium antigens were found in the mesangium and in the capillary walls of 2 patients. After treatment with chloramphenicol, the S. mansoni infection persisted, but the clinical, laboratory, and immunopathological alterations were resolved. These findings suggest a direct role for Salmonella in the pathogenesis of glomerulonephritis described in patients with associated Salmonella and S. mansoni infections.