Hearing loss is the fourth leading contributor to years lived with a disability worldwide. Most recent estimates indicate that one-half of a billion people suffer from disabling hearing loss worldwide. The social and economic burden is significant. When attributing monetary value to years lived with disability owing to hearing loss, there is greater than $US750 billion lost each year globally. There are numerous contributors to hearing loss, including congenital, infectious, noise exposure, age-related, traumatic, and immune-mediated causes. Understanding the pathophysiology of these factors allows for the development of preventative and treatment strategies specific to the underlying cause.