OBJECTIVES: To examine our patients with brucellosis and renal involvement. Although brucellae have been recovered from the urine of patients with brucellosis, renal involvement is uncommon. METHODS: The data from 15 patients (8 males and 7 females, mean age 43 +/- 18.9 years, range 16 to 80), who had been admitted to our hospital with the diagnosis of brucellosis with renal involvement from 1998 to 2006, were retrospectively evaluated. RESULTS: In almost all cases, urinalysis revealed hematuria and variable amounts of proteinuria; some of the patients had pyuria. Of the 15 patients, 14 had renal failure. The etiology of renal failure was prerenal azotemia in 1, acute tubular necrosis because of nonsteroidal anti-inflammatory drug use in 1, anuric tubulointerstitial nephritis due to rifampin use in 1, nephritis accompanied by brucellar endocarditis in 3, brucellar endocarditis and tubulointerstitial nephritis-associated vasculitis in 1, brucellar membranoproliferative glomerulonephritis in 1, and brucellar tubulointerstitial nephritis clinically in 6 patients. Hemodialysis was required in 5 patients. Chronic renal failure developed in 1 patient, 2 patients were lost to follow-up, and renal function completely recovered in 11 patients. Two patients underwent renal biopsy and membranoproliferative glomerulonephritis with intraglomerular infiltration of histiocytes was identified in 1 patient and chronic tubulointerstitial nephritis associated with vasculitis and immune complex nephritis features was identified in the other. CONCLUSIONS: In areas endemic for brucellosis, this infection can be associated with hematuria, proteinuria, and renal failure. In addition, many diverse etiologies can play a role in the renal involvement associated with Brucella infection.