Although auditory training is one of the main elements of aural rehabilitation, its limitations in terms of time and cost give many hearing-impaired adults less opportunity to achieve better speech perception skill. This study develops an auditory training program for mobile devices that was then applied to an adult listener suffering from bilaterally moderate-to-severe sensorineural hearing loss to examine its efficacy. The training program had 4 levels (i.e., discrimination, advanced discrimination, identification with a closed-set condition, and identification with an open-set condition) and each level was planned to be completed in one week. To examine whether the subject achieved enhanced speech perception, the vowel, consonant, and sentence tests before- and after the training were evaluated to compare the two training scenarios. After 4 weeks of auditory training using a mobile device, the results showed that performance in the consonant and sentence tests largely increased except for the vowel test that produced 100% correct scores in before- and after training. These results suggest that a moderate amount of auditory training using a mobile device is effective when it is used to improve the speech perception of hearing-impaired adults.