In clinical audiology, it is important to differentiate whether sensorineural hearing loss is cochlear or retrocochlear, which is distinguished with the presence of recruitment phenomenon. The author investigate the diagnostic value of recruitment phenomenon with Metz test in comparison with SISI test and Bekesy audiometry. In the present study, 34 ears of normal listeners and 101 ears of sensorineural hearing loss were the subjects of investigation and the results were as follows : 1) In all normal listeners, recruitment phenomenon was negative with Metz test and Bekesy audiometry, but 5.8% was positive with SISI test. 2) The rate of recruitment phenomenon positive of suspicious cochlear hearing loss was 70.1% with Metz test, 88.1% with SISI test and 23.9% with Bekesy audiometry. 3) The rate of recruitment phenomenon positive was 66.3% in suspicious cochlear hearing loss and 89.5% in noise induced hearing loss. 4) In cases of noise induced hearing loss, recruitment phenomenon positive was 84.2% with Metz test and 73.7% with SISI test in 4 KHz, that was higher positive rate than the value of other frequencies. 5) In Metz test, there was no difference between the test frequencies, or crossed and uncrossed reflex. 6) The higher pure tone threshold, the less difference between reflex threshold and pure tone threshold, and the latter is inverse proportion to the former. With above results, the author concluded that Metz test is a good objective method to detect the recruitment phenomenon but is should be combined with other tests to diagnose cochlear hearing loss.