This prospective case report series utilized an anterior mandibular positioning (AMP) device on obstructive sleep apnea (OSA) patients and evaluated the changes in the respiratory disturbance index (RDI) and subjective overall satisfaction with the treatment. The RDI was based on all-night polysomnographic studies performed before and after approximately 4 months of appliance use. Overall satisfaction with the treatment was rated using a Likert scale (0 to 10) after 6, 18, and 36 months of AMP device use. Although only 15 of the 24 subjects agreed to undergo post-appliance polysomnograms, 14 of the 15 subjects showed a clear decrease in the RDI. The effect on the other subjects is unknown, but even if the 9 subjects without polysomnograms had no change in the RDI from the AMP device, a minimum rate of 58% of the subjects (14 of 24) would have substantially improved the RDI at the 3-month time point. Of the 24 subjects, 2 subjects claimed no immediate benefit and stopped using the device, 4 subjects were lost to followup, 1 subject lost weight and stopped using the device, 1 subject had mandibular advancement surgery after using the appliance for a period of time, and 3 stopped using the appliance because of persistent temporomandibular pain problems. The remaining 12 of the 23 (52%) original subjects were still using the appliance successfully at 36 months. One subject died of non-apnea-related causes before the 18-month follow-up time point. The 16 subjects who responded at 36 months reported a mean overall satisfaction with treatment of 6.9 +/- 3.3 on a scale of 10.