This study deals with the disguised voice (or voice disguise) in the field of forensic phonetics. We especially studied the effects of the methods of disguised voice on the aural decision. Within the nonelectronic-deliberate voice disguise area, the methods of disguised voice include use of lowered pitch, pinched nostrils, falsetto, and whisper. Ten (male:5, female:5) Seoul speakers made a recording of 16 sentences. In the aural test, 30 subjects listened normal and disguised voice. And they were asked to make a decision whether speakers identified or not. The result is as follows: The speaker verification of the falsetto and whisper was more difficult than the lowered pitch and pinched nostrils.