BACKGROUND: Recently, a lot of cases with microcalcifications of the breast are pointed by the images of mammography (MG), because breast screening using MG become common. Although MG is a gold standard modality for detecting microcalcifications, images of ultrasonography (US) are now feasible to detect microcalcifications with recent improvements to ultrasound diagnostic devices. In this report, we analyzed clinical significance of microcalcifications detected with US images in invasive breast carcinoma. METHODS: Eighty-eight patients with invasive breast carcinoma who underwent MG and US before surgery at the Division of Breast and Endocrine Surgery of Tottori University Hospital between January 2012 and August 2013. After reviewing US images, the association between the presence of echogenic spots that indicate microcalcifications and images of MG or pathological findings was assessed. RESULTS: Patients without microcalcifications on US images were significantly more likely to have the Luminal A subtype and a lower nuclear grading. Conversely, patients with microcalcifications on US images were significantly more likely to have higher level of MIB-1 index, lymphovascular invasion, comedonecrosis and lymph node metastasis. The rate of detecting microcalcifications on US images was relatively good, with 81.8% of sensitivity, 94.5% of specificity and 89.8% of diagnostic accuracy. Among the calcifications detected by MG images, detected rate of calcifications with US images was higher in necrotic type (92.6%) than secretory type (33.3%). CONCLUSION: This study suggest that microcalcifications of tumors detected by US images could serve as an useful prediction to evaluate the degree of malignancy for patients with invasive breast carcinoma.