The axillary lymph node (LN) burden of breast cancer patients guides multidisciplinary management and treatment regimes. Sonographic imaging is used to identify the presence, number and location of axillary LNs suspicious of malignancy and used to guide nodal fine needle aspirations and biopsies. Axillary LNs suspicious of harbouring breast cancer metastasis can be localised to three surgical axillary levels, numbered according to their location relative to the pectoralis minor muscle and lymph flow. To sonographically identify and localise suspicious axillary LNs, an understanding of the axillary anatomy, muscular sonographic landmarks, surgical axillary levels, and the sonographic technique to image and distinguish between benign and suspicious LNs is required.