Purpose: To evaluate the role of ultrasound and Doppler velocimetry in the diagnosis of breast cancer. Methods: Thirty breast cancer patients, diagnosed by clinical examination, mammography and fine needle aspiration, or trucut biopsy were assessed by breast ultrasound including Doppler velocimetry to evaluate blood flow in the axillary and lateral thoracic arteries. Postoperative histopathological examination proved malignancy in all cases. This cohort was compared to another group of 30 patients with proven benign breast disease and a cross-matched control group of 30 asymptomatic women with no breast disease. Results: In the 30 cancer patients, the size of masses ranged from 1-4 cm (2.51 ± 1.13), the mean axillary artery resistance index (RI) ranged from 0.8-0.88 (0.84 ± 0.03), and the lateral thoracic artery RI ranged from 0.45-0.59 (0.55 ± 0.106). However, power Doppler did not detect any increased perfusion. In the benign group, the lateral thoracic artery RI ranged from 0.78-0.86 (0.85 ± 0.8) and the axillary artery RI ranged from 0.81-0.89 (0.81±0.05), while in the control group, the mean lateral thoracic artery RI ranged from 0.85 to 0.89 (0.87 ± 0.082), and the axillary artery RI ranged from 0.84-0.9 (0.88 ± 0.16). Statistical analysis revealed only a high statistical significance (p < 0.01) for the lateral thoracic artery indices between the malignant group as compared to the benign and normal groups. There was no statistical significant difference in the axillary artery RI between the three groups. Conclusion: It is suggested that a marked decrease in the lateral thoracic artery RI with a cut-off value less than 0.6 is highly sug­gestive of malignancy. Taking the pilot nature of the results, further studies with much larger numbers are needed to corroborate such findings.