PURPOSE: To compare power and conventional color Doppler sonography for depiction of the vasculature of solidbreast lesions, and to evaluate the usefulness of power Doppler sonography for differential diagnosis of malignantbreast lesions. MATERIALS AND METHODS: In order to detect vascularity, 82 cases of solid breast lesions wereevaluated by power and color Doppler sonography. Fifty-eight pathologically proven cases (37 benign and 21malignant lesions) were analyzed for the amount and patterns of Doppler signals, morphology of vessels, and thediagnostic accuracy. RESULTS: In 45 of 82 cases, power Doppler sonography depicted flow better than did colorDoppler sonography, while in 37 cases, depiction was equal. On power Doppler sonography, the incidence of markedblood flow in malignant lesions was three times higher than in benign lesions. The pattern of vasculature was morepredominantly central (85.5 %) and penetrating (61.9 %) in malignant lesions than in benign lesions. Branching(57.1 %) and disordered vessels (33.3 %) were more frequent in malignant lesions than in benign. For the diagnosisof malignancy, sensitivity for power Doppler sonography was 65 %, specificity was 79 % and diagnostic accuracy was74.1 % ; for color Doppler sonography, the corresponding figures were 76.9 %, 75.6 % and 75.9 %. CONCLUSION: Power Doppler sonography was more sensitive than color Doppler sonography for the detection of flow in solidbreast lesions. For the differentiation of benign from malignant lesions, however, there was no difference indiagnostic accuracy between the two modalities. findings of central and penetrating distribution patterns ofDoppler signals, and branching and disordered shapes of vessels, along with other sonographic criteria, arehelpful for predicting malignancy.