Thirty-six patients with pure dysgerminoma of the ovary were treated at the University of Texas System Cancer Center, M.D. Anderson Hospital and Tumor Institute between 1947 and 1974. Twenty-six of these patients had their initial surgery at the M.D. Anderson Hospital or were referred to the M.D. Anderson Hospital shortly after surgery at another hospital. The remaining 10 were referred after developing a recurrence of their tumor. Five of the 26 patients who were treated initially at the M.D. Anderson Hospital had only a unilateral salpingo-oophorectomy and are alive and well at the present time. The remaining 31 patients have received postoperative radiotherapy. Ninety-two percent of the patients receiving initial treatment at M.D. Anderson Hospital, and seventy percent of those referred for treatment after recurrence, are surviving at the present time without evidence of disease. The selection of treatment for the individual patient is discussed.