We obtained samples of patellar cartilage at the time of surgery from 20 patients: 11 with normal and 9 with macroscopic cartilaginous degeneration. The glycosaminoglycans were separated by cellulose acetate electrophoresis, and the relative content of major glycosaminoglycans was measured by optic scanning. The total content of glycosaminoglycans was estimated by uronic acid analysis. We found that degenerated cartilage contained an increase in dermatan sulfate and hyaluronic acid and a decrease in chondroitin 6-sulfate and total uronic acid concentration, with only slight changes in chondroitin 4-sulfate and keratan sulfate compared with normal cartilage.