We determined the polyamine contents of the synovial tissues from 11 patients with rheumatoid arthritis (RA), and the free putrescine levels in the synovial fluids (SF) from 10 patients with RA, 7 with osteoarthritis (OA), 5 with posttraumatic arthritis, and 3 with infectious arthritis. Putrescine levels in the synovial tissues correlated with serum C reactive protein concentration in patients with RA. Free putrescine levels in SF were significantly elevated in patients with infectious arthritis, compared with those found in RA, OA, and posttraumatic arthritis. Free putrescine levels in SF from patients with RA were significantly higher than in those with OA. Our findings suggest that polyamines may play an important role in RA.