Twenty cases of a rare tumor, chordoma involving the nasal cavity, paranasal sinuses, or nasopharynx, are reported. Patients most often had localized headache, nasal obstruction, decreased hearing, or symptoms related to cranial nerve involvement, especially diplopia. A mass bulging into the nasopharynx, posterior nasal cavity, or pharynx was found on physical examination in 13 of these 20 patients, and in another 6 patients on radiologic examination. Paralysis of one or more cranial nerves was identified in the majority of patients who had tumors involving the upper nasopharynx. On radiologic examination, bone destruction was frequently identified in the clivus and sphenoid areas, and less commonly in the cervical vertebrae. Each patient had biopsy-proven tumor in the nasopharynx or sphenoid areas. Patients usually were treated by combinations of surgery and radiotherapy, in some cases leading to prolonged periods of apparent tumor control. Radiotherapy frequently resulted in regression of symptoms, sometimes lasting many months or years. A few tumors that involved mainly the lower nasopharynx were more amenable to surgical resection, in one case leading to apparent tumor control. In those cases with adequate follow-up information, most patients had either died of their disease or were living with recurrent or persistent inoperable tumor. Some patients lived for many months or years between recurrences or with known tumor, indicating that chordomas often are slowly growing neoplasms. The histologic features of these chordomas are described and illustrated, and the histopathologic differential diagnosis is discussed.