A total of 18 cases with ovarian carcinoma stage I (15 stage Ia and three stage Ib) were studied retrospectively to evaluate the efficiency of transvaginal color Doppler sonography in detecting the disease in its early stages. Four asymptomatic women (two cases with morphologically normal ovaries, and two with simple unilocular cysts) were found during the screening program. These cases would have been missed without the use of transvaginal color Doppler sonography. One ovary with stage Ia, and another ovary in a case with stage Ib ovarian cancer were missed. These data show the ability of transvaginal color Doppler sonography to detect ovarian cancer as early as stage I even in asymptomatic women as well as in the morphologically normal ovary.