The purpose of this study is to investigate the correlation between surgicopathological findings and ultrasonic images of nonpalpable breast lesions. The study was composed of 220 nonpalpable breast lesions from 193 patients. The breast lesions were classified into soft tissue type (185 lesions) and calcification type (35 lesions). Of the 220 lesions, 62 (28%) were malignant. For soft tissue type lesions, the sonographic features of sound attenuation (p < 0.001) and irregular border (p < 0.001) were significantly associated with the malignant diagnosis. For soft tissue-type and calcification-type lesions, the presence of increased vascularity (p < 0.001) or calcification (p < 0.001) was significantly associated with the malignant diagnosis. Of the 164 breast lesions with corresponding mammograms, 37 of 74 mammographically identifiable lesions were pathologically malignant, as compared with 16 of 90 lesions with negative mammograms (p < 0.001). In our study, the more sensitive sonographic features for predicting malignancy were irregular border and increased vascularity (sensitivity 88% and 82%, respectively), whereas the features of sound attenuation and presence of calcifications were more specific (specificity 88% and 80%, respectively). In conclusion, ultrasound-guided wire localization of breast lesions is not only useful in assisting surgical biopsy, but the sonographic findings obtained by this procedure correlate with pathologic diagnosis.