A light microscopic study of renal biopsy specimens from forty six cases of adult nephrotic syndrome, during a period of 1967 to 1973 at Seoul National University Hospital, was carried out and correlated to the response to corticosteroid therapy. These were classified into minimal change (8 cases), focal glomerulosclerosis (2 cases), mesangial proliferative glomerulonephritis (9 cases), membranoproliferative glomerulonephritis (14 cases), (epi)membranous nephropathy (4 cases), diabetes mellitus (5 cases), and chronic glomerulonephritis (4 cases). The frequency distribution of the three main histological groups was ‘membranoproliferative glomerulonephritis’ 30.4% ’mesangial proliferative glomerulonephritis’ 19.6% and ’minimal change’ 17.4% The much lower incidence of membranous nephropathy was assumed to reflect the use of stricter histological criteria and/or geographical difference. Among 8 cases with minimal changes, who were mostly males, 6 cases revealed complete remission by corticosteroid therapy. Though total 3 cases of focal glomerulosclerosis and membranoproliferative glomerulonephritis responded completely to steroid therapy, most cases with various structural glomerular alterations rather exhibited poor remission by treatment.