Among women with early invasive breast cancer and 1–2 positive sentinel nodes, sentinel lymph node biopsy (SLNB) is non-inferior to axillary lymph node dissection (ALND).1-3 However, preoperative axillary ultrasonography (AxUS) may not be sensitive enough to discriminate burden of nodal metastasis in these patients, potentially leading to overtreatment.4-6 This study compares axillary operation rates in patients who did and did not receive preoperative AxUS, assessing its utility and risks for overtreatment. This is a retrospective cohort study of patients with clinical T1/T2 breast tumors who were clinically node negative and underwent an axillary operation. Patients who had preoperative AxUS received more ALND compared to patients who did not (5.6% vs. 1.4%, p ​< ​0.001). There was no significant difference in the number of additional axillary operations following SLNB (2.1% vs. 2.3%, p ​= ​0.77). Eliminating preoperative AxUS is associated with fewer invasive ALND procedures, without increased rate of axillary reoperations. •Axillary ultrasound in patients meeting Z0011 criteria is linked to overtreatment.•Omitting axillary ultrasound decreases unnecessary ALND in select patients.•Omitting axillary ultrasound does not increase re-operations in select patients.