Ultrasound studies of sixty five patients with thyroid mass histologically proven at KyungPook National University Hospital from June 1983 to May 1984 were retrospectively analized. No specific sonographic characteristics of thyroid mass lesions was found on the basis of histological diagnosis. Authors consider that ultrasound study might be mere useful for detection and localization of a lesion, and guide to needle aspiration, monitoring the size of a mass following therapy as well.