Improvements in breast cancer detection are underway with work being done on different imaging techniques and the assessment of abnormal vascularity. In an earlier study we used a 10 MHz CW Doppler pencil probe. In palpable carcinomas 94% had shown abnormal vascularity. However, in nonpalpable lesions, this method did not allow flow detection in combination with imaging. Recent developments in color flow mapping allow detection of small tumor vessels, which are invisible on B-mode ultrasound. Registration of vessels simultaneously to B-mode imaging allows this method to be used for nonpalpable lesions. The sensitivity of diverse Doppler instruments shows remarkable differences. This makes uniform evaluation of the method difficult. We examined 94 symptomatic women using different equipment. In 9 of 32 carcinomas no Doppler signals were found. However, CW Doppler showed low vascularity in these 9 false-negative cases. However, the variation of vascularity in malignancies does not yet allow routine application of this method and needs further scientific evaluation.