We investigated the usefulness of vacuum-assisted biopsy(VAB)using the EnCor ENSPIRE®system for initial biopsy of breast tumors. We analyzed 24 cases of VAB using the EnCor ENSPIRE®system performed for breast tumors. Of 24 mammary lesions, 12 cases(50.0%)were diagnosed as malignant. Among them, 7 cases(29.2%)were invasive ductal carcinoma(IDC) and 5 cases(20.8%)were ductal carcinoma in situ(DCIS). Six cases required tumor resection for definitive diagnosis; 1 case was diagnosed with IDC, 2 cases with DCIS, 2 cases with intraductal papilloma(IDP), and 1 case with atypical ductal hyperplasia( ADH). Moreover, EnCor ENSPIRE®system biopsy was performed in 15 cases because malignancy could not be diagnosed using core needle biopsy. There were 4 cases of IDC, 4 cases of DCIS, 2 cases of IDP, 2 cases of usual ductal hyperplasia, and 2 cases of ADH. There were no complications due to a series of procedures. We believe that the EnCor ENSPIRE®system is an effective technique having both convenience and great diagnostic accuracy.