The purpose of this study is to evaluate the accuracy of mammography, ultrasonography, and contrast-enhanced magnetic resonance imaging for the diagnosis of intraductal spread of breast cancer following preoperative neoadjuvant chemotherapy. We evaluated a total of 168 areas of normal breast tissue outside the mass in 42 consecutive female patients with breast cancer using each imaging modality both before and after neoadjuvant chemotherapy. Neoadjuvant chemotherapy comprised two to four cycles of adriamycin-based CAF regimen. Multivariate analysis indicated that calcification on mammography and size of hypoechoic structures on ultrasonography prior to neoadjuvant chemotherapy shows a correlation with intraductal spread on pathologic study. Our study reveals that mammography and ultrasonography are useful in avoiding residual cancer cells caused by intraductal spread following conservative breast surgery.