The aim of this study was to investigate the efficacy and toxicity of sulphasalazine (SASP) in the treatment of children with chronic arthritis. The medical records of 36 children (25 boys, 11 girls) who received SASP for the treatment of chronic arthritis were reviewed. Twenty-one patients had juvenile spondyloarthropathies (JSA) (eight juvenile ankylosing spondylitis (JAS), 13 undifferentiated JSA (uJSA) and 15 had juvenile rheumatoid arthritis (JRA). The patients received SASP therapy for a mean of 2.5 years (range 3 weeks to 8.1 years). Clinical and laboratory data were reviewed retrospectively to determine the effects of treatment. A clinically significant response occurred in 23 (64%) children: remission in 14 (39%) (JRA 5, JSA 9) and improvement (25% reduction in joint count) in nine (25%) (JRA 4, JSA 5). There was no difference in response rate between JRA and JSA patients (p = 0.11), but the time to remission was shorter in JSA patients (mean 5 months) than in JRA patients (mean 25 months) (p = 0.024). Twelve of the 36 patients discontinued non-steroidal anti-inflammatory drugs, and six of eight patients discontinued prednisolone. A significant fall in erythrocyte sedimentation rate and rise in haemoglobin occurred in SASP-treated patients (p < 0.005) comparing most recent results with pretreatment levels. Side-effects occurred in four of 36 patients (11%); only one patient who had persisting severe diarrhoea required discontinuation of SASP. It was concluded that SASP appears to be effective and safe in the treatment of JRA and JSA patients. As a second-line agent, SASP is the drug of first choice for patients with JSA; for JRA patients SASP may be a useful, possibly less toxic alternative to methotrexate.