In recent years, ultrasound has become established as part of the diagnostic evaluation of breast tumours. Not replacing, but complementing mammography, ultrasonic investigations increasingly represent a sensitive means of early diagnosis. Thermography, on the other hand, has proved of relatively little value and doesn't play a significant role today. Lately, Colour Doppler sonography has been used for differentiating tumour-associated blood supply patterns--however, sensitivity and specificity were not as high as initially expected. Colour spectrum analysis of local findings in comparison to the remaining glandular tissue, however, seems to be a promising method in the differentiation of ultrasound findings of uncertain tumour status. A fibroadenoma shows no significantly different colour density as compared to surrounding tissue. In carcinoma, on the other hand, one regularly finds a hyperintensive zone with sharp margins. In 70 patients, who had breast tumours, we attempted the differentiation of benign and malignant findings with the help of colour spectrum analysis. Postoperatively, these results were validated by histology. With the exception of one mesenchymal tumour, the Doppler diagnosis was identical to the histopathological findings.