The short answer is no. If you have health coverage through Medicare, you don't need to do anything. It will not affect your coverage.
Among the other questions we're hearing frequently:
Do I need to re-enroll in my Medicare plan through the new health insurance Exchange?
Nope. Medicare's open enrollment is not part of the Exchange. If you are on Medicare, do not sign up for a plan in the Exchange.
Will I lose my Medicare coverage due to health reform and the Exchange?
No. Health care reform and the Exchange do not affect your Medicare coverage. You still have the same benefits and security you have now with Medicare.
Will people on Medicare be fined for not buying a health insurance Exchange plan?
No. In fact, it's against the law for someone who knows you have Medicare to sell you an Exchange plan.
Can I go to the Exchange and get a subsidy to help pay for my Medicare coverage?
Sorry, but no. If you're on Medicare, you're not eligible for the subsidies, which are for people buying coverage through the Exchanges.
For more questions -- including how the Exchange and Medicare work for recent immigrants, for those about to turn 65, etc. -- please see our new "popular questions about Medicare and the Exchange" web page.