Sinonasal undifferentiated carcinoma is a relatively rare and aggressive malignancy of the nose and paranasal sinuses. It is often difficult to distinguish from other poorly differentiated sinonasal malignancies. Since it was first described in 1986, advances have been made in the understanding of the histology and immunohistochemical markers of sinonasal undifferentiated carcinoma, but the treatment options and prognosis remain poor. Presenting signs and symptoms, patient demographics, risk factors as well as immunohistochemical findings are reviewed. While no treatment is standard for sinonasal undifferentiated carcinoma, several modalities and combinations including chemotherapy, radiation, and surgery have been used with varied success. The several case series reported are examined and future directions of therapy discussed.