Two hundred thirty patients with differentiated carcinoma of the thyroid gland received definitive treatment at the University of Texas M. D. Anderson Hospital and Tumor Institute (MDAH), Houston, from January 1960 through December 1975. Two thirds of these patients were women, and 127 of these female patients (55%) had not had any previous treatment. The mean follow-up period was 11.8 years. The vast majority of patients (80%) had mixed papillary and follicular cancers; 104 patients were seen with cervical metastases. Overall absolute survival was 72.6%. The prognosis was more favorable in the female patients and those persons who were treated solely at MDAH. In 4.4% of those patients treated with a total thyroidectomy, the cancer recurred locally. Of those whose operation was only a lobectomy, local recurrence developed in 10.7%. Several adverse prognostic factors were identified in this group of patients. This analysis would suggest the need for a more selective approach to the surgical treatment of this disease. Differentiated cancer of the thyroid gland affects a heterogeneous group of patients and also appears with varied clinical and anatomic manifestations.