The objective of this study was to compare the results of hearing augmentation with the Retro-X semi-implantable hearing aid to a conventional non-implantable open canal hearing aid using the same software technology (Titan-X, auric Hearing Systems, HiKaNo.:13.20.03.0047). Nineteen subjects (20 ears) with mild to moderate high-frequency sensory-neural hearing loss were included in this clinical study. All the subjects were first fitted with a conventional open canal hearing aid (Titan-X). After a period of 4-6 weeks audiological evaluations were performed using standardized speech tests in quiet and noise. Subjective evaluation was performed with the help of standardized questionnaires. After this phase the patients received the semi-implantable Retro-X device under local anaesthesia and 4 weeks later were fitted with a hearing module with the same software technology as the conventional Titan-X hearing aid. Four weeks following the first fitting the same audiological evaluations were performed under similar conditions and the patients were evaluated again using the same questionnaires in order to compare the results of the Retro-X semi-implantable system with the conventional open canal hearing aid. Audiological evaluations revealed better results with the semi-implantable Retro-X in the adaptive speech in noise test; however, the results of the monosyllabic word test in quiet were similar for the Retro-X and conventional open canal hearing aid. The patients subjectively preferred the improved wearing comfort of the semi-implantable device. The Retro-X semi-implantable hearing aid provides better speech perception in noise and higher wearing comfort in comparison to the conventional open canal hearing aids. Considering the simple implantation procedure under local anaesthesia with low complication rate, Retro-X is an alternative to the conventional open canal hearing aids in patients with mild to moderate high frequency sensory-neural hearing loss.