The concept that the triad of diabetes mellitus, obesity, and hypertension is of etiologic and diagnostic significance in endometrial carcinoma was tested in 55 patients with endometrial carcinoma and 114 control patients. Factors which might influence glucose tolerance such as age, parity, obesity, hypertension, family history of diabetes, and anterior pituitary function were evaluated. Both groups consisted of patients who had postmenopausal bleeding and were divided into those with endometrial carcinoma and those with neither endometrial carcinoma nor hyperplasia. Abnormal glucose metabolism and sustained arterial hypertension were no more frequent in patients with endometrial carcinoma than in the controls. There appeared to be no association between increased parity and decreased glucose tolerance nor between the degree of obesity and decreased glucose tolerance. The carcinoma group was significantly more obese and less parous than the control group.