The glycosaminoglycan (GAG) content in human urothelial carcinomas was biochemically determined and compared to that of normal urothelium and bladder wall of the calf. The total GAG content was elevated in urothelial carcinomas, and the distribution pattern differed from that of normal urothelium and bladder wall. Whereas urothelial carcinomas contained heparan sulphate, dermatan sulphate, chondroitin 4-sulphate and chondroitin 6-sulphate, only heparan sulphate could be detected in the normal urothelium. The GAG determination was based on hexosamine analysis and thin layer chromatography after elution on Dowex 1 X 2 columns.