How Often Will Medicare Pay For CPAP Supplies? 
If your doctor certifies that you have sleep apnea that can not be treated with other protocols and you need a cpap machine , Medicare will pay for the rental of a cpap machine . Your doctor must have documented a sleep study where your nightly sleep patterns were monitored . Medicare will cover a 90 day rental . After 90 days your doctor must recertify the need for the machine . 