['Controversy surrounds the reliability of sentinel lymph node biopsy after primary systemic chemotherapy. In this study, we assessed axillary ultrasound for selecting patients most likely to optimally benefit from biopsy.', 'The study included 87 patients who received primary systemic chemotherapy and underwent a sentinel lymph node biopsy followed by axillary lymph node dissection. Lymph nodes >10 mm in diameter, irregularly swollen, round, and homogeneously hypoechoic without an echo-rich center were considered axillary ultrasound positive.', 'In axillary ultrasound-negative patients before and after primary systemic chemotherapy, identification, sensitivity, and false-negative rates were 81%, 100%, and 0%, respectively. However, in patients whose lymph nodes converted from positive to negative after primary systemic chemotherapy, these values were 83%, 70.8%, and 29.2%, respectively.'] Is axillary ultrasound examination useful for selecting patients optimally suited for sentinel lymph node biopsy after primary systemic chemotherapy?