Reviewing the scans of 114 post operative thyroid patients shows that 59 of them (49.1%) had some functioning thyroid tissue in the operated area. As the postoperative scanning periods varied from 1 month to 44 years we could not decide between regeneration or remnants in some of the patients. Some showed remnants a short period after total thyroidectomy, others had complete regeneration several months or years after operation. The postoperative finding occurred in both malignant and benign lesions, namely 17 of 40 patients with carcinoma and 39 of 74 with non-malignant disease.