This report describes the accurate localization of metastatic lesions in a patient with differentiated mixed thyroid cancer using 99mTc-tetrofosmin imaging. A 66-yr-old women with a cytological diagnosis of follicular thyroid cancer associated with a large amount of goiter changes was studied by 99mTc-tetrofosmin total-body scintigraphy. No significant tetrofosmin uptake was observed in the thyroid nodules, which mainly showed goiter abnormalities. Abnormal increased tetrofosmin uptake, however, was found in metastatic tumor lesions located in the cervical and dorsal spine as well as in the left lower chest wall and lungs. In conclusion, 99mTc-tetrofosmin, a new radiopharmaceutical proposed for myocardial perfusion imaging, may be useful in patients with thyroid cancer.