Twenty-nine (50%) of 58 children with thyroid carcinoma received previous ionizing radiation to the head and neck. The average interval to diagnosis was 9.6 years. Fifty-six carcinomas were either papillary, follicular, or mixed differentiated tumors. Two carcinomas were medullary with amyloid struma. There were no undifferentiated carcinomas. Cervical lymphatic metastases were present in 88%. Local infiltration of tumor occurred in 31% and pulmonary metastases in 19%. Fifty-one patients (88%) have undergone total thyroidectomy. Forty-eight patients underwent lymph node excisions ranging from lymph node plucking to bilateral modified and radical neck dissections. Sodium iodide I 131 was administered in therapeutic doses to 49 of the 58 patients in our series. The thyroid carcinoma mortality was 5.2%. There were no deaths in those patients who underwent total thyroidectomy and appropriate regional lymph node dissection, and received therapeutic sodium iodide I 131 when indicated on the basis of follow-up scans.