THE SO-CALLED Hürthle cell tumor of the thyroid represents one of the less common neoplasms of this gland. There are relatively few case reports1 of this malignant tumor as compared with numerous reports of other types of carcinoma of the thyroid. The lesion is of interest from the varied viewpoints of etiology, pathology, and treatment. It is the purpose of this study to report 22 cases of Hürthle cell carcinoma diagnosed and treated on the Yale University Surgical Service and the Grace-New Haven Community Hospital during the years 1927 to 1952 inclusive. The commonly accepted term "Hürthle cell tumor" is a misnomer, and only prolonged usage with subsequent acceptance has prevented the name from being abandoned. The first reported demonstration of the large cells with finely granular, eosinophilic cytoplasm peculiar to this lesion was in 1881 by Baber.2 It was not until 1894 that Hürthle3 demonstrated these