Continuous positive airway pressure (CPAP) is treatment provided by a machine worn at night or during times of sleep to treat sleep apnea, a sleep disorder in which a person regularly stops breathing during sleep for 10 seconds or longer. A CPAP machine increases air pressure in the throat, keeping tissues in the airway from collapsing when a person inhales.

The CPAP machine delivers air through a mask that covers the nose and mouth, through a mask that covers only the nose (nasal continuous positive airway pressure, NCPAP), or through prongs that fit inside the nose. The mask that covers only the nose is used most frequently.

CPAP is the most widely used treatment for sleep apnea caused by blocked airflow in the throat (obstructive sleep apnea).