A simple method was used to isolate hyaluronic acid (HA) and sulfated glycosaminoglycans from synovial fluids obtained from children with juvenile rheumatoid arthritis (JRA) and from normal age-matched controls. The bulk of the glycosaminoglycans present in both normal and pathologic synovial fluids consisted of hyaluronic acid and chondroitin 6-sulfate. The diseased synovial fluids showed a sharp decrease in the concentration of glycosaminoglycans when compared with normal controls. These findings are similar to those reported for the synovial fluid of adult patients with rheumatoid arthritis.