Pleomorphic adenoma, which is also called mixed tumor is considered to occur favorably in major salivary glands such as parotid and submandibular glands, and rarely in the nasal cavity, pharynx, larynx, trachea, and lacrimal gland. We reported here a rare case of pleomorphic adenoma (2.9 X 2.2 X 1.7 cm3) developed from the lateral wall of right nasal cavity in a 43-year-old woman. Statistical observation of pleomorphic adenoma of the nasal cavity in Japan was made and comparative study was also made between such adenoma and that in the parotid gland. In Japan, 41 cases of pleomorphic adenoma originated in the nasal cavity have been reported so far including ours. These cases had age of onset of 16-74 years, averaging 44.6 years. Sex ratio showed female predominance. No significant difference was noted in affected sides sites. Chief complaints were represented mostly by nasal obstruction (29 cases; 71%) and nasal bleeding (23 cases; 56%). Tumors were surgically extirpated in all cases. One recurrent case (2.4%) was reported and another malignant case (2.4%) was also reported. 4 cases (9.8%) were originated in the lateral wall of nasal cavity and all of the other cases were in the nasal septum. In comparison with pleomorphic adenoma developed in parotid gland in Japan, sex ratio was 1:1.8 compared with 1:2.1 for parotid gland with almost similar tendency. Age of onset averaged 44.6 compare with 32.8 years for parotid gland, with a little advance in age.(ABSTRACT TRUNCATED AT 250 WORDS)