Background – Mandibular advancement device (MAD) has been described as an alternative treatment to the severe obstructive sleep apnea (OSA), once it is not as effective as the continuous positive airway pressure therapy (CPAP) in reducing the apnea and hypopnea index (AHI). Case report– We report a case of a 55 years old male who presented with moderate sleep apnea. Polysomnography report shows the AHI score of 50 that is diagnosed a severe sleep apnea. Mandibular Advancement Device (MAD) was planned for the treatment of sleep apnea. Conclusion – Mandibular advancement device resulted in increase in the upper airway space. This ultimately helped in the therapeutic treatment of snoring and improved quality of life.