ObjectivesThe purpose of this study was to investigate the association of demographic factors, grade, margin status, and treatment modalities for overall survival in patients with sinonasal mucoepidermoid carcinoma (SNMEC).Study DesignRetrospective database review.MethodsThe National Cancer Database was queried for patients of all ages with SNMEC between 2004 and 2015. Univariate Kaplan‐Meier and multivariate Cox regression analyses were performed to evaluate the association of suspected prognostic factors with overall survival. Subgroup analysis by margin status and grade was performed.ResultsA total of 239 patients with SNMEC were included in the analysis. The 5‐year overall survival was 63.6%. Prognostic factors associated with decreased survival include age over 70 years (P = .027), sphenoid primary site (P = .002), and advanced‐stage malignancy (P = .024). Improved survival was associated with surgery achieving negative margins (P = .001). Adjuvant radiation was associated with improved survival (hazard ratio [HR] = 0.25, P = .015) in the negative‐margin group but was not found to be a statistically significant factor in the positive‐margin group (HR = 0.66, P = .509).ConclusionsThis investigation is the largest to date to analyze the association of treatment modalities with overall survival in SNMEC and subgroup analysis by histopathologic grade and surgical margin status of treatment outcomes. Surgery remains the mainstay of treatment in patients with SNMEC. However, administration of radiation may confer survival benefit to patients with negative margins.Level of Evidence4 Laryngoscope, 2020