ABSTRACT Background Sinonasal undifferentiated carcinoma (SNUC) is a high‐grade, aggressive neoplasm. Low incidence and poor outcomes make identification of prognostic factors and treatment standardization difficult. Similarly, little is known regarding the association of human papillomavirus (HPV) with SNUC. Methods A retrospective review was conducted. Extracted information included treatment received, tumor recurrence, patient survival, p16 expression, and HPV status. The Kaplan–Meier method was used to estimate overall survival (OS) and disease‐free survival (DFS). Survival trends were compared using the log‐rank test. Results Nineteen patients received multimodality treatment for SNUC. Five‐year OS and DFS rates were 45.2% and 50.7%, respectively, with no significant difference between treatment types. Tumors from 11 patients were p16‐positive and 9 of these were also HPV‐positive. Kaplan–Meier analysis demonstrated improved survival. Conclusion Our series demonstrates a higher prevalence of HPV in SNUC than previously reported. HPV‐positive SNUCs may benefit from improved survival and should be investigated further in future studies. © 2014 Wiley Periodicals, Inc. Head Neck 37: 366–374, 2015