Medicare Part D began on January 1, 2006

Medicare Part D is the prescription drug coverage program that started on January 1, 2006. Congress created it as part of the Medicare Modernization Act, passed in 2003. Before Part D existed, Medicare covered hospital stays and doctor visits, but not the cost of prescription medications — a gap that left many seniors paying full price for drugs.

The program launched as a voluntary benefit, meaning you could choose to join a Part D plan or stay without drug coverage. That choice still exists today. When Part D began, it was a significant shift in how Medicare worked, because for the first time, private insurance companies — not Medicare itself — handled the actual drug coverage and payments.

Understanding when Part D started matters because it affects your current coverage options and any penalties you may owe if you did not join when you first became may be able to access. The rules about timing have stayed largely the same since 2006, even though the plans and costs have changed.

Key Takeaways

  • Medicare Part D launched on January 1, 2006, adding prescription drug coverage to Medicare for the first time.
  • Private insurance companies run Part D plans under contract with Medicare, not Medicare directly.
  • Joining Part D is voluntary, but delaying enrollment without other drug coverage can result in a permanent penalty on your premiums.
  • The initial enrollment period for Part D was from November 2005 through May 2006, and similar windows open each year during the Annual Enrollment Period.
  • Part D coverage has changed every year since 2006 — plans, drugs covered, and costs shift annually.

Why Congress created Part D in 2003

Before 2006, Medicare paid for hospital care and doctor visits but left prescription drugs entirely to the patient. By the early 2000s, drug costs were rising faster than any other part of healthcare, and seniors on fixed incomes were making difficult choices — skipping doses, cutting pills in half, or going without medications altogether.

The Medicare Modernization Act, signed into law in December 2003, was Congress's response. It created Part D as a way to help seniors afford medications while keeping the program run by private insurers rather than by Medicare itself. This structure — private plans competing for enrollees — was intentional. Lawmakers believed competition would keep costs down and give seniors choices.

The law also included a coverage gap, often called the "donut hole," which limited how much Medicare would pay once you reached a certain spending threshold. That gap has shrunk over time but still exists in some form on most plans today.

How Part D enrollment worked in 2006

When Part D launched, Medicare gave people a six-month window to join: November 15, 2005, through May 15, 2006. If you were already on Medicare by November 2005, you could enroll during this initial period without penalty. Coverage began on January 1, 2006, for anyone who signed up by December 31, 2005.

The enrollment process was new and confusing for many seniors. Medicare mailed information packets, but choosing among dozens of plans — each with different drugs covered, different pharmacies, and different costs — was overwhelming. Many people joined the first plan they saw or the one their doctor recommended, not realizing they could switch every year.

If you did not join during that initial window and did not have other drug coverage, you faced a penalty. That penalty — a percentage added to your Part D premium — was designed to discourage people from waiting until they got sick to sign up. The penalty structure from 2006 is still in place today.

What Part D covered when it started

The original Part D plans in 2006 covered a broad range of prescription drugs, but not all of them. Each plan made its own list of covered medications, called a formulary. Some plans covered brand-name drugs more generously; others pushed generic versions. Insulin, heart medications, and antibiotics were typically covered, but coverage for newer or less common drugs varied widely by plan.

The coverage gap — the donut hole — was a major limitation from day one. Once you and your plan had spent $2,250 on covered drugs in 2006, you entered the gap and paid the full price for medications until your out-of-pocket spending reached $3,600. Then catastrophic coverage kicked in and Medicare paid most of the cost. This gap meant many seniors with serious chronic illnesses hit the donut hole every year.

Over time, the Affordable Care Act (passed in 2010) gradually closed the donut hole. By 2020, the gap was much smaller, and seniors paid only 25 percent of drug costs while in the gap instead of the full price. The structure continues to change, so your coverage this year may differ from last year.

How Part D has changed since 2006

Part D was not static after launch. The number of available plans has grown from dozens in 2006 to hundreds today, varying by state and region. The drugs covered have changed every single year — some medications get added to formularies, others are removed or moved to higher cost tiers. Premiums have risen, though not always at the same rate as other healthcare costs.

The biggest change came from the Affordable Care Act in 2010, which gradually eliminated the donut hole and added free preventive medications for seniors. In 2023, Congress passed the Inflation Reduction Act, which capped out-of-pocket drug costs at $3,500 per year for Medicare beneficiaries — a major shift from the previous unlimited costs.

Technology has also changed how Part D works. In 2006, you had to call a plan or visit in person to enroll. Today you can compare plans and enroll online through Medicare.gov, though many seniors still prefer phone support or in-person help at local senior centers.

Who had to enroll in Part D and when

If you turned 65 and enrolled in Medicare in 2006 or later, you had a seven-month window to join Part D without penalty — the month you turned 65 plus six months after. If you missed that window and did not have other drug coverage, a penalty applied to any Part D plan you joined later.

The penalty was calculated as 1 percent of the national average Part D premium for each month you were not enrolled. In 2006, that was roughly $35 per month, so waiting a year could add $35 to your monthly premium permanently. The penalty amount changes each year based on the national average premium.

People who had drug coverage through a former employer or union, or through Medicaid or the Veterans Administration, did not face a penalty for delaying Part D enrollment. The rule was — and still is — that you need some form of drug coverage to avoid the penalty, but it does not have to be Part D.

How to find out about Part D coverage today

Every year during the Annual Enrollment Period (October 15 through December 7), you can review your current Part D plan and switch to a different one if you want. Medicare.gov has a plan comparison tool where you can enter your medications and see which plans cover them and at what cost. You can also call 1-800-MEDICARE to speak with someone who can walk you through your options.

If you are newly may be able to access for Medicare or turning 65 soon, you have a seven-month window to join Part D without penalty. That window starts the month you turn 65 (or the month you first become may be able to access for Medicare if that is later). Missing this important date can cost you thousands of dollars over time in penalties, so it is worth understanding your options early.

Many local Area Agencies on Aging offer free counseling to help you understand Part D and choose a plan. You can find your local agency by calling the Eldercare Locator at 1-800-677-1116 or visiting eldercare.acl.gov.

Frequently Asked Questions

Do I have to join Part D when I turn 65?

No, Part D is voluntary. You can decline coverage if you have drug coverage from another source — an employer, union, Medicaid, or the VA. If you have no other drug coverage and do not join Part D, you will face a penalty if you enroll later. The penalty is permanent and added to your monthly premium for as long as you have Part D.

What happens if I missed the enrollment important date in 2006?

If you were may be able to access for Medicare in 2006 and did not join Part D then, you can still enroll today, but you will owe a penalty unless you had other drug coverage during the gap. The penalty is calculated based on how many months you were without coverage. You can enroll during the Annual Enrollment Period (October 15 through December 7) each year, or if you have a may have access to life event, at other times.

Can I switch Part D plans after I join?

Yes. You can switch plans once per year during the Annual Enrollment Period, which runs from October 15 through December 7. Your new coverage begins January 1. If you have a may have access to life event — such as losing other drug coverage, moving to a new state, or a significant change in your health — you may be able to switch outside the enrollment period.

Why does my Part D plan change every year?

Insurance companies update their Part D plans annually. They change which drugs are covered, which pharmacies are in the network, and how much you pay. Your current plan may no longer cover a medication you take, or the cost may increase. That is why it is important to review your plan each year during the Annual Enrollment Period and switch if a different plan would save you money.

What if I cannot afford my Part D premiums?

You may be able to get help paying Part D premiums through the Low-Income Subsidy program, also called "Extra Help." This program is run by Social Security and is based on your income and resources. You can explore through Social Security online, by phone at 1-800-772-1213, or in person at your local Social Security office. Your state Medicaid office can also help you explore.