Optimal treatment for thyrotoxicosis remains controversial in adults, but more so in paediatric practice. We have conducted a retrospective review of the records of 76 paediatric patients seen between 1965 and 1995 to determine management practice and outcome of therapeutic interventions. Seventeen are currently on antithyroid drug (ATD) treatment, while four have had their care transferred. Of the remaining 55, 21 (38%) achieved long-term remission with ATD alone following a mean treatment duration of 3.3 y (range 0.5-7 y). Block-replacement (high dose of ATD with thyroxine replacement) was more convenient than the titration regimen (3.4+/-0.3 visits to hospital per year versus 6.1+/-0.4, p<0.001). Surgery (subtotal/total thyroidectomy) was carried out in 27 patients, of whom 24 subsequently became hypothyroid and were treated with thyroxine. I131 was used successfully in six patients, two following surgery. ATD should remain the first-line therapy; a block-replacement regimen is more convenient. Surgery in a specialized centre carries a low risk. Caution should still be exercised in the use of I131 in young children.