Medicare Glossary

Annual Enrollment Period (AEP)

The period each year from October 15 through December 7 when Medicare beneficiaries can change their Medicare Advantage or Part D drug plans. Changes take effect January 1 of the following year.

Also known as: Fall Open Enrollment

Disenrollment

The process of leaving a Medicare Advantage or Part D plan. You can only disenroll during specific enrollment periods, such as the Annual Enrollment Period or a Special Enrollment Period. When you disenroll from a Medicare Advantage plan, you return to Original Medicare.