Home/Glossary/Initial Enrollment Period (IEP)Glossary · EnrollmentInitial Enrollment Period (IEP)A 7-month window around your 65th birthday during which you first enroll in Medicare: 3 months before, your birth month, and 3 months after.Related TermsAnnual Election Period (AEP)General Enrollment PeriodSpecial Enrollment Period (SEP)Medicare Advantage Open Enrollment (MA-OEP)SHIPLate Enrollment PenaltyCOBRAEmployer Group Health Plan← Back to glossary index