ABSTRACT Background Sinonasal localization of Ewing's sarcoma in adults is an exceedingly rare event. Methods The clinical records of 5 patients with primary sinonasal Ewing's sarcoma treated from 1992 to 2012 were retrospectively analyzed. All pathologic slides were reviewed by 2 experienced pathologists. All patients underwent multimodality treatments. Results Median age was 36 years (range, 25–52 years). At referral, 2 patients had the original diagnosis changed by review of the histologic slides. Tumors were classified as T4aN0M0 (4 patients) and T2N0M0 (1 patient). Median follow‐up was 110 months (range, 70–139 months). Only 1 patient, who started treatment elsewhere based on an incorrect histologic diagnosis, experienced multiple recurrences and eventually died of widespread metastasis. Conclusion Correct pathologic diagnosis can have a crucial impact on treatment planning and outcome. Multimodality therapy is the key for long‐term successful results. Because of the rarity of the tumor, referral to highly experienced care centers is strongly recommended. © 2016 Wiley Periodicals, Inc. Head Neck 39: E45–E50, 2017