To clarify the characteristics of HBV-associated renal lesions, renal biopsies obtained from 22 HBsAg seropositive patients(M:F=32:1) were studied. Other than two(age 4 and 12), all were adults(17-77 y.o.). Twelve of the patients had nephrotic syndrome(NS), 5 NS and hematuria(H), 10 proteinuria and H, one gross H, one microscopic H, and 4 normal urinalysis at the time of biopsy. Light microscopy showed minimal change lesion(MCL) in 9 cases, mesangial proliferative glomerulonephritis(MSPGN) in 6, MPGN type I in 7, MPGN type III in 6, and mebranous nephropathy(MGN) in 5 cases. There were variable immunofluorescent(IF) findings of 25 cases studied; IF staining were predominant with IgG in 10 cases, with IgA in 5 and with IgM in 2 cases. Complements tended to be more strong for C1 &/or C4 than C3. In electron microscopic(EM) studies of MCL group, rare mesangial deposits were noted(3/5). In MSPGN, aside from mesangial deposits, there were occasional subendothelia(2/4) or subepithelial(1/4) deposits. In MPGN type I, in addition to the usual EM features of MPGN, some subepithelial deposits were also observed in 5 cases. In MGN, 3 out of 4 showed subendothelial deposits. Among 7 cases stained for HBsAg all were negative with IF and 2 were positive with PAP method. It is concluded that clinico-pathological findings of HBV-associated nephropathy are variable and partly show lupus-like features, different from primary glomerulopathy.