The acidic glycosaminoglycans (AGAG) in normal human kidneys were fractionated on Dowex 1-X2 columns and analysed by electrophoretic separation in three buffers on cellulose acetate membranes and gel filtration on Sephadex G-100 columns, before and after digestion with chondroitinases and streptomyces hyaluronidase. Thin-layer chromatography was also performed to separate glucosamine from galactosamine moieties. Enzymatic digestion combined with electrophoretic characterization indicated that heparan sulfates exist as the main AGAG which accounted for two-fifths of the total AGAG. Hyaluronic acid and dermatan sulfates accounted for one-fourth and one-sixth of the total kidney AGAG, respectively. Chondroitin sulfate isomers (4-sulfate and 6-sulfate) consisted of the residual one-sixth of the total AGAG. An oversulfated chondroitin sulfate was detected in a small amount by demonstration of the unsaturated disulfated disaccharide after digestion with chondroitinase-ABC but not with chondroitinase-AC.