Abstract: Nontoxic goiter refers to thyroid gland enlargement without hyperthyroidism.Thyroid hormones suppressive therapy is not effective in shrinking large goiters.For those with high surgical risk or refused to surgery, a nonoperative reduction of the thyroid volume would be desirable. Iodine-131 therapy for volume reduction in non-toxic goiter is a safe, cost-effective and effective treatment. This makes this form of therapy a more choice for patients with large nontoxic goiter.