Sinonasal teratocarcinosarcoma is an extremely rare malignant tumor arising in the sinonasal tract, having combined histological features of teratoma and carcinosarcoma. Here, we are presenting a case of sinonasal teratocarcinosarcoma in a 28-year-old male patient. A 28-year-old male patient presented with left-sided nasal obstruction and recurrent epistaxis for last 2 months. On examination, a polypoid mass was noted in the left nasal cavity. The mass was surgically resected. Paraffin-embedded sections were made and stained with hematoxylin and eosin. Microscopic examination revealed intimate admixture of carcinomatous (adenocarcinoma), sarcomatous (chondrosarcoma), primitive neuroendocrine and teratoid elements (immature squamous elements). These findings clearly suggest the diagnosis of sinonasal teratocarcinosarcoma. Sinonasal teratocarcinosarcoma is highly malignant and locally aggressive. About 60% of the patients do not survive beyond 3 years. Total excision and extensive sampling are necessary to reach the diagnosis. Early diagnosis and management can give a better prognosis.