Sinonasal teratocarcinosarcoma (SNTCS) is a very rare and aggressive malignant neoplasm histologically characterized by the combination of one or many components of epithelial and mesenchymal elements. Here, we report a SNTCS in a 60-year-old man involving posterior nasal and nasopharyngeal wall extending into left ethmoidal sinus. The patient complained of bleeding from nose, nasal obstruction, and generalized weakness for last two months. Tumor was completely removed by Caldwell-Luc operation and postoperative radiation therapy was given. The follow-up of the patient for two years has shown no evidence of recurrence or metastasis.