Calcifying cystic odontogenic tumor (CCOT) is a rare histologic subtype of odontogenic tumor. Treatment requires complete enucleation. We report what we believe is the first case of CCOT to be removed via a transnasal endoscopic approach. A 16-year-old boy was referred to our department by his dentist for evaluation of an expansile mass of the left maxillary sinus. The dentist had noted an area of hyperlucency of the left palate during a routine examination. Computed tomography confirmed the presence of a large tumor. Complete resection of the tumor was achieved via a transnasal endoscopic surgical approach. Resection of odontogenic tumors is necessary because of their tendency to expand and produce a mass effect on surrounding structures. We believe resection via an entirely transnasal endoscopic approach is a valuable and important technique in the treatment of odontogenic tumors that leaves the patient with a more cosmetically acceptable postoperative appearance.