ln the period between 1985 and 1991, 83 postmenopausal women with endometrial cancer were examined by transvaginal sonography. None of them were on hormone replacement therapy and all had amenorrhea of more than 2 years. Twenty-two were asymptomatic and had an endometrial cancer detected by transvaginal sonography and 61 showed atypical bleeding as their only clinical symptom. Women with asymptomatic endometrial cancers detected by transvaginal sonography exhibited significantly less mean myometrial tumor infiltration and more well-differentiated tumors than chose with atypical bleeding (4 mm and 45% compared with 10 mm and 18%, respectively). In 75% of the cases the estimation by transvaginal sonography of tumor stage completely agreed with the histological staging. These preliminary data show that asymptomatic endometrial cancers screened by transvaginal sonography ave likely to have a better prognosis than symptomatic cancers. Furthermore, transvaginal sonography can be used as a reliable tool for tumor staging prior to surgery or radiotherapy.