Background: Locally advanced breast cancer (LABC) can be caused by a variety of breast neoplasms. The use of mammography with sonography to estimate pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) has a good degree of precision. Aim of work: To evaluate the precision of breast sonomammography in determining LABC response to neoadjuvant chemotherapy. Subjects and methods: A total of 54 female patients with locally advanced breast cancer were included in the study, which was conducted prospectively from August 2019 to May 2020, they were sent to the Zagazig University Radiology Department and hospitals by the General Surgery and Oncology Departments. A thorough medical history (personal, past, present, and family) was collected, as well as a thorough physical examination. All subjects had bilateral digital mammography as well as a traditional B-mode ultrasonography examination. Before neoadjuvant treatment, a sonomammographic evaluation of the tumour size and morphometric criteria was performed. Biopsy processes were done for suspected breast masses. After finishing the NAC 1:4 weeks previous to surgery, a sonomammographic evaluation of the tumour size and morphological criteria was conducted. Results: There was significant association between post chemotherapy diameters and different breast subtypes in radiological assessment. HR-/HER2- were the most subtype to show radiological response followed by HR+/HER2- while none of HR-/HER2- show response to NAC. Conclusion: In patients with LABC, mammography and breast ultrasonography are regarded more reliable techniques for assessing tumour size and nodal staging of breast cancer subtypes prior to or after treatment.