A retrospective review was undertaken on all renal biopsies performed in Chinese children under 13 years of age in Queen Mary Hospital, Hong Kong from 1980 to 1990. Of 172 renal biopsies, 18 cases were diagnosed to be membranous glomerulonephritis. All were associated with hepatitis B virus infection. Fourteen patients presented with, and 3 others developed later nephrotic syndrome. Hematuria was a common feature (83%). Complement C3 was low in 5 cases and they became normal later. At last observation, 10 patients (59%) remitted, usually within 3 years. One had persistent proteinuria and 5 had nephrotic syndrome. One patient developed end-stage renal failure 12 years after onset of illness. All three female patients completely remitted. Of the 15 boys, 50% remitted whether they received steroid treatment or not. Two patients received interferon alpha-2a therapy. One achieved remission but HBsAg and HBeAg persisted. The other had transient seroconversion and clinical improvement but nephrotic syndrome returned after stopping treatment.