SUMMARY The objective of the study is to assess whether a smartphone application (App) designed to improve hearing can improve audiological performance in patients with normal hearing and with varying grades of hearing loss (HL). This is a multicentre prospective analytical study. We performed a battery of audiological tests consisting of pure tone audiometry (PTA) and a word recognition test (WRT) in quiet and in noise at different signal-to-noise ratio (SNR) using or not a smartphone App. Intra-subject results under both conditions were compared to determine the App’s effect on hearing. A survey was also carried out to obtain data on subjective hearing experience with the App. We recruited 55 HL patients and 13 normal-hearing controls between June to December 2017. The results show that use of the App in HL patients improved WRT scores by a mean of 30.3% in quiet, 24.3% in noise + 10 dB SNR, and 20.8% in + 5 dB SNR. App use was identified as a factor that increased word recognition (odds ratio = 1.812, p < 0.05) and 61% of subjects rated sound quality when using the App as good or excellent. The use of a smartphone hearing App improved scores in both PTA and WRT in most cases. Patients with binaural hearing impairment < 60% obtained the best results. Subjective user satisfaction was good in both conditions.