It, has been reported that there are some differances between malignant and benign t,umor in the wave forrn of the intraturnoral or surface arterial blood flow. Transvaginal Doppler ultrasound with color flow imaging was used in 24 with ovarian tumor before explorative laparotomy. The impedence of wave forms were analysed using values nf pulsatility index (PI). Transvaginal sonographic (TUS) scoring systern and CA 125 were also checked before operation. The sensi tivity of Pl was 100%, compared with those of TVS scoring system (75%) and CA 125 (63%) even though the specificity of PI (81.3%) was less than those of TVS scoring system (87.5%) and CA 125 (93.8%). But, in the early stage of cancer the sensitivity of PI (100%) is quite higher than those of TVS scoring system (60%) and CA 125 (40%). Based on the results transvanginal Doppler color flow imaging may he a useful clinical tool in the differential diagnosis of malignant, ovarian tumor.