Radio-guided sentinel lymph node biopsy in early-stage breast cancer is standard of care. Freehand SPECT is a system for intraoperative visualization of radioactivity in the body. It generates a 3-dimensional image of the radioactivity distribution complementing the acoustic information of the gamma probe by providing depth and radioactive uptake information. In the reported case, freehand SPECT was used in a breast cancer patient as a control method after conventional sentinel lymph node biopsy. Freehand SPECT identified an additional lymph node, changing the original stage from pN1(mic) (micrometastasis) to pN1a (nodal positive), resulting in an axillary lymph node dissection.