We retrospectively reviewed the cases of 85 patients with primary sinonasal malignancies who had undergone endoscopic surgery with curative intent achieved by “regional resection.” Our goal was to assess the efficacy of endoscopic surgical treatment vis-à-vis traditional open surgery. Kaplan-Meier data analysis revealed that the 1-, 3-, and 5-year disease-specific survival rates were 82, 60, and 49%, respectively. Multivariate Cox model survival analysis revealed that male sex, certain pathologic types of cancer (i.e., undifferentiated carcinoma, olfactory neuroblastoma, and rhabdomyosarcoma), and T3/T4 category negatively impacted survival (adjusted hazard ratios: 3.601, 0.012, 0.287, 0.068, and 0.339, respectively; p < 0.05 for all). We also performed a separate analysis of 47 patients who had category T3 or T4 cancer to determine if the type of surgical approach is a prognostic factor. For this, we identified 20 new patients who had undergone open resection, and we compared them to 27 of our endoscopically treated patients who had similar clinical characteristics. We found that the type of surgical approach did not appear to be a prognostic factor (p > 0.10), although those patients who had undergone endoscopic resection had significantly shorter hospital stays (p < 0.001). We conclude that patients with primary sinonasal malignancies who are treated with endoscopic surgery have acceptable survival rates and therefore endoscopic surgery is justified in the hands of highly experienced surgeons in selected cases.