PURPOSE: To evaluate the usefulness of ultrasound-guided mammotome biopsy for complete removal of the imaged abnormality through the assessment of success rate in 6-months follow-up ultrasound. MATERIALS AND METHODS: Over a 13-month period, one hundred seventy ultrasound-guided mammotome biopsies were performed in 141 patients. In 143 ultrasonographically benign-appearing masses, complete removal was attempted. Ultrasound (US) was then performed immediately following the procedure and 6 months after to assess whether residual lesion was present or not. The success rate of removal of breast masses was evaluated on 6 months follow-up US. The relationships between the depth and size of breast lesions and the presence of residual lesions was evaluated as well as the amount of hematoma. RESULTS: The mean size of lesions was 1.0 cm (0.3-3.2 cm). 136 of 143 lesions were histologically benign while the remaining seven lesions (4.9%) were histologically malignant or borderline lesion and were operated within a month. 20 residual lesions except scar-like change were noted in 108 lesions on 6-months follow-up US. The assessment for the presence of residual lesion was different in 10.1% between post-procedural and 6-months follow-up US evaluations. The success rate of complete removal was 81.5% (88/108) on 6-months follow-up US. The residual lesions were more frequently observed in case with a larger size lesion and the larger amount of hematoma during the procedure (p <0.01) while showing no correlation with the depth of lesions. CONCLUSION: Complete removal of breast mass lesion on breast ultrasound using ultrasound-guided mammotome biopsy is feasible but cannot be assured. The success depends on the size of lesions and the development of hematoma.