The authors report the results obtained with color Doppler sonography in the study of breast conditions. Color Doppler allows to detect the following main features in breast conditions: the presence of blood flow, vessel arrangement, vascularization extent, the number of vascular poles. To investigate slow flows, it is better to use low PRF values (not above 1 KHz) and low filters, while amplification should be set immediately above the system's noise threshold; the size of color Doppler box should be adjusted as small as possible to maximize sensitivity and minimize flash artifacts. In May 1992 to September 1997, 252 patients with solid breast masses were examined with mammography, B-mode, color Doppler and power Doppler sonography (only 57 cases). We identified histologically (176 cases) or cytologically (77 cases) 141 carcinomas and 112 benign solid lesions. The diameter of the 141 carcinomas ranged 0.4-4 cm (mean 1.7), while the diameter of benign lesions ranged 0.7-3 cm (mean 1.5). The malignancy pattern was characterized by hypervascularity (92.9%), irregular and abundant (54.2%) vascularization and more than one vascular pole. Benign lesions were avascular (43.4%) with poor and peripheral vascularity (90%) and mostly showed only one vascular pole. The avascular cancers (10 cases) were three mucoid, five in situ and two small (0.7 and 0.9 cm) invasive ductal carcinomas. The six benign lesions with irregular and abundant vascularization and more than one vascular pole were proved to be two proliferating and three juvenile fibroadenomas and one phylloid tumor. These results are encouraging and suggest that this technique can be a useful adjunct to mammography and sonography in the differential, diagnosis of breast nodules.