A young woman aged 23 years, with non-toxic goiter was treated in our Department. Serum levels of FT4, FT3 and TSH were within normal range, high resolution ultrasonography show very large glands (60 ml), with large nodule in left lobe and smaller one in the right lobe. Malignancy was ruled out by ultrasound-guided fine-needle aspiration biopsy. Thyroid radioiodine scintigraphy showed homogenous and diffuse uptake in the right lobe, with very low uptake in the left lobe, radioiodine uptake (RAIU) after 24 and 48 h was 29 and 27%. The effective half-life measured by the use of RAIU was about 7 days. The patient refused surgical operations and agreed to be treated with radioiodine. The activity dose was calculated by Marinellis formula and the patient received 280 MBq of I-131. The absorbed dose was about 240Gy. Follow up control was done every 4 weeks. After 6 months of radioiodine therapy, thyroid scintigraphy showed homogenous and diffuse uptake in the left lobe and very low uptake with reduction of the size of right lobe. Thyroid USG also show a decrease in the volume of right lobe. RAIU after 24 and 48 h was 36 and 35% respectively. The patient received a second dose of radioiodine 600 MBq, the absorbed dose was about 300 Gy. Thyroid USG and thyroid scan were done after 12 months to assess thyroid volume. The patients received L-thyroxin replacement therapy for hypothyroidism. Thyroid volume decreased about 53%. Radioiodine therapy is non-invasive, safe and cost effective method of therapy for reduction of goitre even in patient with low radioiodine uptake and should not be restricted to elderly, or to patients with high operative risk, but should be used as first choice in every patient with non-toxic nodular goitre (>40 ml) especially in patients with special professions or patients wish a non-invasive treatment modality.