Doppler ultrasound is an adjunct to other imaging modalities in differentiating benign from malignant breast tumors. Two groups of patients with breast nodules were examined using a 10/4.5 MHz (imaging frequency/pulsed Doppler frequency) image-directed Doppler probe and a 7.0/5.0 MHz color Doppler imaging probe, separately. Whenever flow signals were detected within or at the margin of the breast nodule, the lesion was considered to be malignant. In detecting malignant breast tumors, the sensitivity was 77.3% and 94.5%, specificity 83.3% and 40.1%, accuracy 81% and 63.4% for image directed Doppler and color Doppler imaging, respectively. We found color Doppler to be easier and more efficient in detecting the flow signals of neovascularity in breast tumor. Color Doppler exhibits a higher sensitivity in detecting the malignant breast tumors. However, more false-positive diagnoses were made. Color Doppler ultrasound also expedited the examination, and the whole procedure could be shortened from 35 minutes to 8 minutes compared with our previous examination performed by image-directed Doppler ultrasound. Due to its higher sensitivity and saving in examination time, we use color Doppler imaging as a routine procedure when solid lesions are observed in x-ray mammography or sonography, as a supplement to the diagnosis of breast tumors.