Congenital hearing loss is a relatively common disease, occurring in 1–2 out of every 1000 newborns, and it has been reported that 60–70% of cases of bilateral severe-to-profound hearing loss are hereditary. Identification of the gene that causes hearing loss allows us to pinpoint which cells in the inner ear are dysfunctional, making it possible to develop precision medical strategies for treatment. Treatments include HAs and CI depending on the degree of hearing loss, but these are merely symptomatic treatments, and it is expected that gene therapy will be used to secure proteins necessary for hearing as a fundamental treatment. Further, progress has been made in drug treatments that aim to improve hearing loss through elucidation of the mechanisms of hearing loss and blocking the processes that cause hearing loss. As examples, this chapter introduces the recently launched gene therapy for hearing loss caused by OTOF variants and drug therapy for NLRP-related hearing loss. Genetic diagnosis will become indispensable for the further development of such precise treatments based on molecular diagnosis.