Determining sentinel lymph nodes (SLNs) in breast cancer staging involves subjective interpretation by the surgeon. We hypothesized patient and tumor characteristics influence number of SLNs harvested.A single-institution, prospectively collected database was queried for breast cancer patients undergoing SLN surgery (2002–2013) and mean SLN counts were compared.There were 2394 SLN biopsies. Mean number of SLNs per patient for the entire cohort was 2.6. Mean number of SLNs removed was greater for patients ≤50 years (2.9 versus 2.6; p < 0.0001). Fewer SLNs were removed with tumors ≤1 cm (2.5 versus 2.6; p = 0.002). Patients with grades 2 or 3 tumors had more SLNs removed than grade 1 (2.6 versus 2.5; p = 0.03). Receipt of neoadjuvant therapy was associated with more SLNs removed (3.0 versus 2.6; p = 0.005).Number of SLNs removed varies based on risk factors for SLN metastasis or false-negative SLN biopsy.