Objective: The objective of this study was to compare the underestimation rate of invasive carcinoma cases with ductal carcinoma in situ (DCIS) at percutaneous ultrasound-guided core biopsies of breast lesions between 14-gauge automated core needle biopsy (ACNB) and 11-gauge vacuum-assisted biopsy (VAB), and analyze the diagnostic advantages and insufficiencies in DCIS between this two methods, and to determine the relationship between the lesion type (masses or microcalcifications on radiological findings) and DCIS underestimation rate. Methods: We collected 152 breast lesions which were diagnosed as DCIS by retrospectively reviewing data about ultrasound-guided biopsies of breast lesions (from February 2003 to July 2010). There were 98 lesions in 95 patients by 14-gauge ACNB, and 54 lesions in 52 patients by 11-gauge VAB (The system used in this study called Mammatome, MMT). The clinical and radiological findings were reviewed; meanwhile all the selected patients had histological results of the biopsies and follow-up surgeries which also achieved the reliable pathological results to compare with the biopsy results. The differences between two correlated histological results defined as underestimation, and the histological DCIS underestimation rates were compared between the two groups. According to the radiological characteristics, each group was classified into two subgroups (masses or microcalcifications group), and the differences between subgroups were also analyzed. Results: The DCIS underestimation rate was 45.9% (45/98) for 14-gauge ACNB and 16.6% (9/54) for MMT. According to the lesion type on ultrasonography, DCIS underestimation was 31.0% (26/84) in masses (43.1% using ACNB and 12.1% using MMT; P = 0.003) and 42.6% (29/68) in microcalcifications (48.9% using ACNB and 23.8% using MMT; P = 0.036). Conclusion: The underestimation rate of invasive carcinoma in cases with DCIS at ultrasound-guided core biopsies is significantly higher for ACNB than for MMT. Furthermore, this difference does not alter among the two lesion types presented on ultrasonography. So ultrasound-guided VAB (MMT system) could be an effective and useful method for the diagnosis of DCIS lesions no matter what the lesion type is. © 2013 Springer-Verlag Berlin Heidelberg.