Hepatitis B virus (HBV)-related membranous nephropathy (MN) is prominent in secondary nephrotic syndromes (NS) in Africa, but the features of this disease and the spectrum of associated glomerulopathies have not been adequately documented in black children. HBV was detected in 93 children with NS included in this study. In 70 patients the histological type was membranous; 46 were followed for a mean of 3.4 years (range 1-11 years). Spontaneous elimination of both HBsAg and HBeAg occurred in 10 (21.7%) patients; 16 (34.8%) cleared HBeAg alone. Co-existing liver disease occurred in 18 (25.7%) and hypocomplementemia (C3,C4) in 47.1% and 11.4% of children, respectively. Sixty-five (92.9%) patients had normal renal function, 1 (1.4%) impaired renal function, 3 (4.3%) chronic renal insufficiency, and 1 (1.4%) end-stage renal disease at last hospital visit. Twelve patients were in remission, all having cleared HBeAg. HBVMN was clinically indistinguishable from 24 children with idiopathic MN, although biochemical characteristics were different. This report delineates the natural history of HBV infection in black South African children with NS, the majority of whom have MN. Disease remission in HBVMN parallels elimination of HBV antigens, particularly HBeAg. Comparison of HBVMN with idiopathic MN revealed clinically indistinguishable characteristics but unexplained biochemical differences.