[en] Objective: To investigate the therapeutic effects and safety of ¹³¹I treatment on children and adolescents with Graves disease. Methods: In this study, 89 children and adolescents with Graves hyperthyroidism cases were treated using ¹³¹I. ¹³¹I was given at a dosage of 2.59 to 4.44 MBq per gram of thyroid tissue and calibrated according to the course of disease, thyroid weight, and the highest iodine rate. The treatment was via oral medication on an empty stomach once a day. All cases were required to undergo a proper medical follow-up at the end of 3, 6, and 12 months after treatment and once a year later. The cure, hypothyroidism rates and incidence rates of benign and malignant thyroid tumors and the health of their offspring were studied. The safety of radioiodine treatment for children and adolescents' growth, development were also evaluated. Results: Follow-up was conducted on 80 cases, with 30 males and 50 females, aged from 6 to 19(12.2 ± 2.3) years; nine patients were lost to follow-up(10.1%). The maximum dose of ¹³¹I ranged from 177.6 to 555 MBq per patient; the mean dose was 203.5 MBq. After one year of radioiodine treatment, the cure rate was 82.50%, and the effective rate was 98.75%; no efficiency is very low(1.25%). As time passed, the incidence of hypothyroidism increased, reaching 35% within 15 years. All cured patients had normal growth and produced offspring whose intelligence and development were normal. No one was diagnosed with thyroid carcinoma or leukemia in his/her medical follow-ups. Conclusions: Using ¹³¹I for treating children and adolescents with Graves hyperthyroidism was effective and safe. The minimal side effects make it worthy of wide application in clinics. (authors)