CHAMPVA rules require that (if you turn 65 on or after June 5, 2001) you must enroll in both Medicare Parts A and B when you become eligible at age
65. If you do not, you lose your CHAMPVA benefits. However, you do not have to enroll in Medicare Part D prescription drug coverage in order to remain in CHAMPVA.
Once you are enrolled in Medicare Parts A and B, Medicare becomes the primary payer of your medical bills while CHAMPVA becomes the secondary payer. That means that CHAMPVA only pays a certain portion of the bills that are covered by both Medicare and CHAMPVA but that Medicare does not fully pay for. For more information about CHAMPVA and Medicare, see the Department of Veterans Affairs web site's CHAMPVA page[va.gov].