Objective To evaluate the safety and effectiveness of totally implantable heating aid (Carina) was assessed in adult patients with bilateral moderate to severe hearing loss. Methods Surgical implantations of Carina were performed in three adult patients with bilateral moderate to severe hearing loss. The safety and effectiveness were evaluated in a more than 12 months follow-up by comparison of outcomes of PTA and speech audiometry pre and post-operatively. The daily usage of implants was observed and compared with traditional heating aids. Results The average elevation of unaided threshold elevation on surgical side was 8. 3 dB postoperatively. The average functional gain in four speech frequencies of PTA was 35.4 dB HL and the average threshold decrease of speech discrimination was 22. 5 dB HL. The subjective scoring of performance of the implants is significantly higher than traditional heating aid. Conclusions Totally implantable hearing aid (Carina) is an ideal implant to treat moderate to severe hearing loss. Long term follow-up is needed to validate the results.