This report describes the correlation of pathological findings with transvaginal color Doppler sonography performed preoperatively on 26 ovarian masses. The pulsatility indices of benign lesions (1.9 +/- 0.7) were higher than those of malignant ones (0.7 +/- 0.2) (p = 0.03). Low pulsatility indices (< 1.0) were found in three relatively vascular benign lesions (one immature teratoma, one cystadenoma containing a dermoid cyst, one endometrioma), causing an overlap between the pulsatility indices of some benign and malignant masses. There appears to be significant potential for discrimination between benign and malignant ovarian masses with transvaginal color Doppler sonography.