Although hysteroscopy is generally recognized as the primary diagfinostic procedure for evaluating intrauterine disorders, it is of limited usefulness in evaluating uterine conguration and lesions in the myometrium. To evaluate its diagnostic efficacy, we used sonohysterography to examine patients with uterine disorders. The subjects were one hundred thirteen patients with normal menstrual cycles and suspected intrauterine disorders. First, a flexible 5.5 Fr. or 8 Fr. catheter fitted with a balloon was introduced into the cervical canal, and the endometrial cavity was then fully inflated with a 10% glucose solution and observed by tran- svaginal ultrasound. The endometrium appeared as separate layers during the normal menstrual cycle and became thicker from the proliferative to the periovulatory phase. Its thickness remained constant during the periovulatory and the secretory phases, however. Sonohysterography visualized intrauterine lesions more precisely than did transvaginal ultrasound in cases of intrauterine disorder, especially in leiomyomas, endometrial polyps, and endometrial carcinomas with myometrial invasion. Sonohysterography proved to be a simple and repeatable method that can be used to diagnose and differentiate intrauterine disorders.