lmpedance audiometry requires physical modifications during the test, which might influence retest data. Therefore, in Order to interprete retest data meaningfully, the range of variation should be identified in each measure of impedence audiometry. The present study obtained data on the retest variation of peak pressure, acoustic reflex threshold, static compliance and earcanal volume in impedance audiometry. ln addition, the authors wanted to know whether or not impedance data would assist otolaryngologists in the detection of conductive hearing impairment. The variation of the retest data was not clinically nor statistically significant in the measurement except for those of ear canal volume. The data on ear canal volume also suggested that the ear canal increases in size during the teenage period and that male ear canals are larger than those of females in ears over 20 years of age. The impedance data assisted the otolaryngologist in the detection of conductive hearing impairment.