ObjectivesTo evaluate the impact of facility volume on outcomes following primary endoscopic surgical management of sinonasal squamous cell carcinoma (SNSCC). MethodsThe 2010–2016 National Cancer DataBase (NCDB) was queried for patients diagnosed with T1-T4a SNSCC surgically treated endoscopically as the primary treatment modality. Factors associated with overall survival (OS) were evaluated, including facility volume. ResultsA total of 330 patients who underwent endoscopic surgical management of SNSCC were treated at 356 unique facilities designated as either low-volume (LVC; treating 1–2 cases; 0-75th percentile), intermediate-volume centers (IVC; 3–4 cases total; 75th–90th percentile), or 144 high-volume (HVC; treating 5+ cases total; >90th percentile) centers. HVC treated patients with higher T staging (42.1 % vs. 29.8 %) and tumors in the maxillary sinus (26.9 % vs. 13.2 %) and ethmoid sinus (10.3 % vs. ≤8.3 %), while LVCs treated lower T stage tumors (70.2 % vs. 57.9 %) and tumors that were located in the nasal cavity (70.2–78.5 % vs. 62.8 %). On multivariable analysis, factors associated with decreased OS included higher T stage (T3/T4a vs. T1/T2; OR 1.92, 95 % CI 1.06–3.47) and older age (>65 vs. <65; OR 2.69, 95 % CI 1.62–4.49). Cases treated at high-volume centers were not associated with a higher likelihood of OS when compared to low-volume centers (OR 0.70, 95 % CI 0.36–1.35). ConclusionsHVC are treating more primary tumors of the maxillary and ethmoid sinuses and tumors with higher T stages with endoscopic approaches, although this does not appear to be associated with increased OS. Short summarySinonasal squamous cell carcinoma (SNSCC) presents late in disease process with poor prognosis. We investigated the impact of facility volume on outcomes following endoscopic treatment of SNSCC. High-volume centers treat more advanced and complex disease with comparable OS.