A technique is described using 1-131-sodium iodine and Tc-99m-sodium pertechnetate for localizing functioning thyroid tissue in the neck following total thyroidectomy. The procedure consists of obtaining a 1-131 thyroid scan. If functioning thyroid tissue is found, it can be localized by means of skin markers as well as a swallow using Tc-99m-sodium pertechnetate. The procedure is safe, simple, and cost efficient and provides a means of localizing functioning thyroid that may influence subsequent therapy.