In this study, two perception experiments were conducted to investigate the misperception of Japanese words with devoiced vowels and/or geminate consonants by young and elderly listeners. In Experiment 1, eight young normal-hearing listeners participated under a white-noise condition, and eight elderly listeners participated in Experiment 2. Two types of word sets which consist of combinations of vowels (V = /i, u/) and voiceless consonants (C = /k, t, s/) were used as stimuli. The first word set involved two- or three-mora words and the second word set had 14 minimal pairs of CVC (:) V, where (:) stands for with or without a geminate consonant. The results of both experiments showed that misperception was great for words with devoiced vowels and even greater for words with geminate consonants. In particularly, the misperception of consonants including high frequency components such as /shi/ or /shu/ was observed for elderly listeners.