Medicare is a federal health insurance program covering a wide range of services that help keep us healthy and aging well. For most people, Medicare eligibility begins shortly before turning 65. But as that time approaches, the decisions we’re asked to make about coverage can feel overwhelming. That includes whether or not to choose a prescription drug plan.

Unlike original Medicare (Parts A and B), which is mandatory, Part D prescription coverage is optional. It's offered through private insurance companies to anyone with Medicare. You can buy Part D as a stand-alone plan or as part of a privately offered Part C (Medicare Advantage) plan. Medicare Advantage plans include the same mandatory benefits provided by Parts A and B and usually include drug coverage, too.

Which prescription drug plan is right for you? This guide covers all the information you need to make an informed decision about signing up for Medicare Part D.

Do I need Medicare Part D?

Probably. Medicare Part D helps pay for prescription medications and protects you from high drug costs today (and in the future). Because most of us will need to take one or more prescription drugs at some point during our lives, having a plan that covers them usually makes a lot of sense.

Can I delay enrollment in Part D and keep my current drug coverage?

If you’re age 65 or over and still working—and you’re covered by a prescription drug plan provided by your employer—you can keep that plan and put off signing up for Part D without penalty. This is true until you retire or lose coverage for another reason.

But there’s a catch. Your employer’s prescription drug plan must provide “creditable coverage.” This means the benefits are “as good as or better than” what Medicare Part D offers. That’s why it’s important to check with your employer to see if you’re eligible to delay enrollment in a Part D plan. If you are, be sure to ask for an official letter from the insurance company that confirms “creditable coverage.”

If you receive prescription drug benefits through your spouse or the Veterans Administration, you also may delay enrollment in Medicare Part D—as long as that coverage is creditable.

For more information on delaying Part D enrollment, check out our “65 and Still Working” guide.

Can I delay enrollment in Part D if I don’t have creditable drug coverage?

If you delay enrolling in Part D and don’t have creditable drug coverage, you may have to pay full price for your medications. And you could face a late enrollment penalty if you go 63 days or more without creditable coverage after your Initial Enrollment Period (IEP). Your IEP is the seven-month window around when you first get Medicare (Parts A and/or B).

The Part D late enrollment penalty is a monthly fee added to your premium. It’s calculated as 1% of the national base premium ($38.99 in 2026) for each month you went without coverage, rounded to the nearest 10 cents. This amount is added to your monthly premium.

In most cases, the Part D late enrollment penalty lasts as long as you have Medicare drug coverage—even if you switch plans. Because the national base premium can change each year, your penalty amount may also change annually.

Note: If you’re eligible for Extra Help, also known as the Part D Low-income Subsidy (LIS), you’re not subject to a late enrollment penalty.  Learn more about the Extra Help benefit, worth about $5,700 yearly. 

Can I enroll in Part C / Medicare Advantage instead of Part D to get drug coverage?

Medicare Advantage (Part C) plans are available through private insurers who contract with Medicare. Medicare requires these plans to cover all the same benefits as Medicare Parts A and B; some Medicare Advantage plans also include prescription drug coverage.

If you sign up for a Part C plan that covers prescription medications, you do not have to enroll in Part D. 

How do I enroll in Medicare Part D for the first time?

There are a few ways you can enroll in a prescription drug plan:

• Use the Medicare Plan Finder: The easiest method is to visit Medicare.gov and compare drug plans based on your medications and pharmacy.
• Enroll directly with plans: You can call a private insurance company directly to enroll in their specific Part D plan, or visit their website.
• Call 1-800-MEDICARE: Call 1-800-633-4227 to enroll in a Part D plan over the phone. TTY users can call 1-877-486-2048. 

Where can I get help understanding Part D plans and costs?

If you or an older adult you know needs help choosing a Part D plan, contact your local State Health Insurance Assistance Program (SHIP). SHIPS are federally funded to provide free, unbiased assistance to people with Medicare and their families. To find your SHIP, call toll-free 1-877-839-2675 or visit the SHIP website.

Need help affording prescription drugs, groceries, and other daily essentials? Visit BenefitsCheckUp®, NCOA's free online tool where you can browse benefits programs that can help you stay healthy and independent. One of these programs is the Part D Low-Income Subsidy (LIS), also called "Extra Help." If you have low income and qualify, Extra Help can save you thousands each year on your prescription medications.