In areas where iodized salt is not available, oral iodized oil is often used to correct I deficiency despite a lack of consensus on the optimal dose or duration of effect, particularly in children, a main target group. Annual doses ranging from 400 to 1000 mg have been advocated for school-age children. Because lower doses of iodized oil have been shown to be effective in treating I deficiency in adults, the aim of this study was to evaluate the efficacy and safety of a low dose of oral iodized oil in goitrous I-deficient children. Goitrous children (n 104, mean age 8.4 years, range 6-12 years, 47% female) received 0.4 ml oral iodized poppyseed-oil containing 200 mg I. Baseline measurements included I in spot urines (UI), serum thyroxine (T4), whole blood thyroid-stimulating hormone (TSH), and thyroid-gland volume using ultrasound. At 1, 5, 10, 15, 30 and 50 weeks post-intervention, UI, TSH and T4 were measured. At 10, 15, 30 and 50 weeks, thyroid-gland volume was remeasured. At 30 and 50 weeks the mean percentage change in thyroid volume from baseline was -35% and -41% respectively. The goitre rate fell to 38% at 30 weeks and 17% at 50 weeks. No child showed signs of I-induced hypo- or hyperthyroidism. UI remained significantly increased above baseline for the entire year (P < 0.001); the median UI at 50 weeks was 97 micrograms/l, at the World Health Organization cut-off value (100 micrograms/l) for I-deficiency disorders risk. In this group of goitrous children, an oral dose of 200 mg I as Lipiodol (Guerbert, Roissy CdG Cedex, France) was safe and effective for treating goitre and maintaining normal I status for at least 1 year.