In this multicentre pilot study of sulphasalazine in juvenile chronic arthritis, the mode of onset and course of the disease, and when available, the HLA status, was recorded on the entry form. After appropriate clinical and laboratory appraisal, sulphasalazine up to 40 mg/kg/day was given for one year with assessments at 0, 1, 3, 6, 9 and 12 months. Fifty-one patients enrolled, 8 of whom were withdrawn because of side effects. In the remainder by 12 months a good effect was noted in 12, 8 having pauci-articular onset disease commencing after the age of 9 years, of whom 6 carried HLA B27. It was relatively ineffective in the other subgroups. The frequency and severity of side effects was similar to that seen in adults. Further evaluation in controlled trials is required in older onset pauci-articular arthritis, taking due note of the patient's HLA status, and also in juvenile psoriatic arthritis and seropositive juvenile rheumatoid arthritis.