Contrast-enhanced computed tomography (CE-CT) is one of the most sensitive imaging modalities. CE-CT plays a role in the following: (1) to determine the extent of breast cancer to select the appropriate breast conserving treatment (BCT). The sensitivity and specificity for the detection of extensive intraductal component (EIC) by CE-CT were 82-88% and 75-89%, respectively. The pathological extent of tumors significantly correlated with the extension revealed by CE-CT; (2) to determine the extent of resection following neoadjuvant chemotherapy, which is difficult to assess by other modalities; (3) to diagnose axillary lymph node metastasis. The sensitivity and specificity are 79-90% and 70-89%, respectively; (4) to identify occult breast cancer with axillary metastasis and to diagnose local recurrence after BCT.