Objective: To determine the efficacy, benefit, and safety of a new in-the-mouth bone conduction device (SoundBite Hearing System) for single-sided deafness (SSD). Study Design: A multicenter, controlled, nonrandomized prospective unblinded study of SSD patients wearing the device. Settings: Ambulatory care centers typical of those where SSD patients are diagnosed and treated. Patients: Adults (ages > 18 and < 80 yr) with acquired, permanent SSD (N = 28) and no current use of any SSD device. Intervention: Continual daily wear of the new device over a 30-day trial period. Main Outcome Measures: The Hearing in Noise Test (HINT), the Abbreviated Profile of Hearing Aid Benefit (APHAB), comprehensive pretrial and posttrial medical, audiologic, and dental examinations and an SSD questionnaire. Results: The Hearing in Noise Test scores improved an average of -2.5 dB after 30 days, compared with wearing no device (p < 0.001). The Abbreviated Profile of Hearing Aid Benefit scores improved (p < 0.05) for all subjects for the Global and Background Noise subscales and for all but 1 subject for the Reverberation and Ease of Communication subscales. There were no medical, audiologic, or dental complications. Conclusion: The SoundBite system is safe and effective and provides substantial benefit for SSD patients with continual daily use over a 30-day period.