Prescription requirements for CPAP supplies vary depending on the equipment and location. In most countries, a CPAP machine itself requires a medical prescription from a doctor or sleep specialist, as it is classified as durable medical equipment. However, many accessories and supplies have more relaxed requirements. Replacement masks, hoses, filters, and humidifier chambers can often be purchased without a prescription from online retailers, medical supply companies, or drugstores, though some suppliers may request one. In the United States, Medicare and private insurance typically require a prescription to cover CPAP equipment costs, but cash purchases from online sellers often do not. It's worth noting that obtaining a prescription is straightforward—most sleep clinics or primary care doctors will issue one after a sleep apnea diagnosis. Even if not legally required for a purchase, having a prescription ensures insurance coverage and helps you get the correct equipment specifications for your needs. Some suppliers maintain prescription requirements as part of their business practices even when not legally mandated. If you're looking to replace specific parts or supplies, contacting your equipment supplier directly will clarify their particular policies. Getting a prescription also provides medical oversight to ensure the CPAP settings and equipment are appropriate for your condition.