Background Outcome studies on sinonasal malignancy are limited to retrospective case series, often with inclusion of diverse histology and short follow-up. The objective of this study was to identify key predictive variables that independently impact survival for paranasal sinus squamous cell carcinoma (SCC) and adenocarcinoma (AC) and to compare these variables in the context of these two distinct clinicopathologic entities. Methods: Analysis was conducted using the Surveillance, Epidemiology, and End Results database from 1973 to 2012 to identify key variables that impact survival for SCC and AC. Results A total of 3,714 cases were included. There were 2,895 SCC cases and 819 AC cases. The mean age at diagnosis was 64.1 years. The male to female ratio for SCC and AC was 1.85 and 1.04, respectively. Patients with SCC and AC were most often diagnosed with stage IV disease in 61.8 and 63.4% of cases, respectively. The majority of patients received combined surgery and radiation (52% for SCC and 43.1% for AC). For SCC, increased age ( p < 0.001) and stage ( p < 0.001) were negative predictors, and surgery improved survival ( p < 0.001) on multivariate analysis. For AC, prognostic factors associated with worse survival include increased age ( p < 0.001) and grade ( p < 0.001) on multivariate analysis. Overall survival was significantly higher in AC compared with SCC at 5 years ( p = 0.001). Conclusion SCC and AC of the paranasal sinuses are both aggressive malignancies with poor survival. For both histological subtypes, increased age predicts worse survival and grade also closely links to survival in AC. These data have important potential implications for treatment planning and pretreatment counseling.