Hysterography can be valuable in the diagnosis of large submucous fibroids. These tumors, when they occupy the entire uterine cavity, form a false smooth wall and are difficult to detect by curettage. In the cases to be reported here, curettage was done for menometrorrhagia by different gynecologists without disclosing the nature of the lesion. Because bleeding continued, hysterography was performed and a large submucous fibroid was found in each instance. Case Reports Case I: R. P., a 27-year-old nullipara, was first seen on May 27, 1948, complaining of irregular bleeding for the last eighteen months. Her menses started at the age of thirteen and until the present illness occurred every thirty days, lasting six days. Treatment had consisted mainly of hormones, administered by mouth, without any effect. The basal metabolism rate, determined three months before admission, was −25 per cent. Three grams of thyroid were administered daily with no effect on the menometrorrhagia, and a repeat basal metabolism test on May 2, 1948, showed a rate of −6 per cent. Physical examination revealed no evidence of any abnormality except for the pelvic findings. The cervix was eroded; the uterus was not enlarged but was retroverted. On June 29, 1948, a diagnostic curettage was performed and a small amount of tissue was obtained. No irregularity of the uterine cavity was noted. Microscopic examination revealed proliferative endometrium, and the patient was discharged on July 1 in good condition. Two weeks later bleeding again started. Ergotrate and Oreton were administered, with slight diminution of the bleeding. After three months of intermittent spotting, a hysterogram (Fig. 1) was obtained on Oct. 11. This showed the uterine cavity to be globular in outline, retroverted, and normal in size. A filling defect occupied the entire cavity and a presumptive diagnosis of submucous fibroid was made. On Oct. 16, the patient was prepared for a vaginal hysterotomy. Prior to this operation, a second diagnostic curettage, performed by a different operator, again revealed no evidence of an intrauterine lesion. When the cervix was incised and a finger introduced into the uterus, a submucous fibroid the size of a walnut was detected. It was attached to the posterior wall by a broad pedicle. This was excised and the patient made an uneventful recovery. Follow-up examination revealed a well healed cervix that readily admitted a uterine sound. Since operation, there has been no abnormal bleeding. Case II: A. L., a 25-year-old nullipara, was first seen on Jan. 14, 1949, complaining of considerable bleeding for the last two weeks, with the passage of clots. In March 1948 there had been a similar episode, for which a diagnostic curettage was performed. There was no evidence of any intrauterine tumor, and a diagnosis of functional bleeding was made. Hormones by mouth were administered at that time to check the bleeding, but without success. The hemoglobin was 54 per cent.