Adenoma malignum (minimum deviation adenocarcinoma) is a rare neoplasma of the uterine cervix, the diagnosis of wich cannot be determined by cervical smear. Recently, magnetic resonance imaging (MRI) was reported as useful for its diagnosis, but differentiation of adenoma malignum from deep-seated nabothian cysts remains problematic. We report here a case of adenoma malignum of the uterine cervix, for which MRI findings could not neglect deep-seated nabothian cysts. However, transvaginal power Doppler ultrasonography clearly showed richness of small vessels, whose arterial flow had higher velocity in the diastolic phase, around the cystic lesion of the uterine cervix. These findings indicate that, at least in the case reported here, transvaginal power and pulsed Doppler ultrasonography is a useful tool for the diagnosis of adenoma malignum of the uterine cervix.