The echo-enhancing effect of an ultrasound contrast medium (Levovist) in color Doppler sonography of small vessels in ovarian tumors was studied in a group of 30 women. The vascularity of adnexal masses with a suspicion of primary carcinoma in 3 and benign lesions in 27 cases was investigated before and after injection of 300 mg/ml of Levovist. In 17 cases color flow mapping showed increased vascularity either in the cystic wall or in solid structures within the tumor. In all patients we observed enhancement of Doppler signal intensity. Our results show that Levovist facilitates waveform analysis in very small vessels with poor velocity patterns.