Inclusion Criteria:

1. Subject is ≥ 18 years old
2. Subject understands the nature of the procedure and has signed the Subject Informed Consent Form prior to the procedure
3. Subject is willing and able to comply with specified follow-up evaluations and understands the audiological test procedures and use of the Esteem® System.
4. Subject has moderate to severe sensorineural hearing loss in the ear to be implanted defined by pure tone average air-conduction threshold level.
5. Subject has an unaided maximum word recognition score of greater than or equal to 40% with recorded delivery using a phonetically balanced word list at SRT + 40 decibels (dB) or at maximum tolerable presentation level.
6. Subject is a current user of a properly functioning and appropriately fit hearing aid for at least one (1) month in the ear to be implanted.
7. Subject has normally functioning eustachian tube
8. Subject has normal tympanic membrane
9. Subject has a normal middle ear anatomy
10. Subject has adequate space for Esteem® System implant determined via fine cut temporal bone CT scan
11. Subject is a native speaker of the English language.

Exclusion Criteria:

1. Subject has a history of post-adolescent chronic middle ear infections, inner ear disorders or recurring vertigo requiring treatment, disorders such as mastoiditis, Hydrops or Meniere's syndrome or disease
2. Subject has a history of otitis externa or eczema for the outer ear canal and the investigator believes this will affect the Esteem® System implantation
3. Subject has cholesteatoma or destructive middle ear disease
4. Subject has life expectancy of < two (2) years due to other medical conditions
5. Subject has retrocochlear or central auditory disorders
6. Subject is known to be suffering from any psychological, developmental, physical, or emotional disorder that the investigator feels would interfere with the surgery or follow-up testing
7. Subject has a known history of fluctuating air conduction and/or bone conduction hearing loss over a one-year period of 15 dB in either direction at 2 or more frequencies (from 500 - 4000 Hz)
8. Subject has sudden hearing loss due to unknown cause
9. Subject has a history of disabling tinnitus, defined as tinnitus which required treatment.
10. Subject is unable to adequately perform audiological testing
11. Subject has a medical condition or undergoing a treatment that may affect healing and the investigator does not believe the subject is a good candidate for the trial.
12. Subject has diabetes that is not well controlled with medication or diet and the investigator does not believe in his best medical judgment that the subject would be a good candidate for the trial
13. Subject is pregnant at the time of device implant
14. Subject has a history of keloid formation
15. Subject has known hypersensitivity to silicone rubber, polyurethane, stainless steel, titanium and/or gold