The efficacy and safety of sulfasalazine for the treatment of juvenile spondyloarthropathy were evaluated in an open study. Twenty-three patients (17 boys and 6 girls) with juvenile spondyloarthropathy inadequately controlled by nonsteroidal antiinflammatory therapy were given sulfasalazine in an average dosage of 39 mg/kg/d. After 3 months, 20 patients exhibited marked clinical improvement; of these 20, 14 discontinued or reduced their nonsteroidal antiinflammatory drug. Mean erythrocyte sedimentation rate fell significantly from 36.8 to 13.7 mm/h. After 12 months. 78% of the patients were in remission. Sulfasalazine was stopped in five patients of which none had evidence of disease relapse 6 to 12 months later. Side effects were infrequent: 2 patients had a skin rash requiring drug withdrawal and two developed mild neutropenia. These data suggest that sulfasalazine is an effective and safe second-line drug for the management of severe juvenile spondyloarthropathies.