Best Medicare Part D Prescription Drug Insurance Companies for 2024

Based on our evaluation of government 5-star quality score ratings

Each year the government rates the quality of Medicare Part D prescription drug insurance plans with a 5-star quality score. An overall quality score is assigned to each plan which is based on the scores of various quality metrics.

Medicare Part D plans provide prescription drug coverage and Medicare beneficiaries can compare plans based on annual government 5-star quality rating scores.

In this article we show the best Medicare Part D health insurance companies by State. Our rankings are based on calculating average overall quality score ratings of all Part D prescription drug plans offered by each insurance company within each State.

State Best Part D Insurance Companies for 2024
District of Columbia
North Carolina
North Dakota
New Hampshire
New Jersey
New Mexico
New York
Rhode Island
South Carolina
South Dakota
West Virginia


What Are Medicare Part D Prescription Drug Plans?

Medicare Part D is how many beneficiaries choose to get their drug coverage. Prescription drugs are not covered by Parts A and B of Original Medicare, so you’ll need a separate plan to help with drug costs. Or, if you are enrolled in a Medicare Advantage plan, you may have Part D included in your plan.

How to Choose the Right Prescription Drug Plan

Every beneficiary has access to multiple prescription drug plans based on their zip code. Each plan has different premiums, drug formularies, and cost-sharing amounts. However, there are a few things to consider when choosing your Part D plan. 

Drug Formulary. Most importantly, you’ll need to compare your current list of medications to those covered by the plan’s drug formulary. The formulary lists all covered prescriptions and categorizes them into drug tiers, which dictate your coinsurance amounts.

Expected Costs. In addition to a monthly premium, you’ll have coinsurance costs when you refill your medications. You may also have an annual deductible. With the help of a Medicare specialist, you can determine how much each of your medications will cost each month on a certain plan.

Networks. You want to fill your prescriptions at a preferred pharmacy. Pharmacies can also be standard or out-of-network. Preferred pharmacies offer the best pricing and least out-of-pocket expenses. You may also want to find out if the plan offers mail-order refills. This option is often more convenient and may even include a discount.

When Can I Enroll In a Medicare Part D Plan?

Several enrollment periods pertain to Medicare Part D prescription drug plans, which are the same enrollment periods as Medicare Advantage plans. Your first opportunity to enroll in a Part D plan is during your unique Initial Enrollment Period (IEP). Your IEP is a 7-month window around your 65th birthday. You can enroll in Parts A and B and choose to enroll in Medicare Part D during this time. Coverage will begin no earlier than the month you turn 65.

If you decide to postpone your transition into Medicare until past the age of 65, you’ll be able to enroll when your current coverage terminates. This often happens to those who decide to continue working and are already covered by an employer’s group health policy. 

Possibly the most important time of year for Medicare beneficiaries is the Annual Enrollment Period (AEP), which begins on October 15 and lasts through December 7. During this time, you can choose to enroll in Medicare Part D for the first time, or you can change your current Part D prescription drug plan. Changes go into effect on January 1.

Medicare Part D members also have an Open Enrollment Period from January 1 through March 31. You may make a one-time change to your current Part D plan during this period. Changes go into effect the following month.

More About Government Medicare 5-star Quality Score Ratings

Each October the government releases updated 5-star quality ratings for Medicare Part D prescription drug plans. The government calculates an “Overall star rating” based on ratings for sub components including “Health plan star rating” and “Drug plan star rating”, which includes further subcomponents of each.

Sub components of Health Plan Star Ratings

  • Drug plan customer service - evaluation of how the health plan handled members’ phone calls, requests, questions, and other interactions related to prescription drug coverage.
  • Member experience with drug plan - based on surveys and member feedback regarding experiences using their Medicare prescription drug plan.
  • Drug safety and accuracy of drug pricing - evaluation of whether members with certain medical conditions are prescribed drugs in a safe and clinically recommended manner. This rating also incorporates the accuracy of the plan’s pricing information.
  • Member complaints and changes in the drug plan’s performance - evaluation of how often members of the plan had problems and filed complaints. Scoring also factors in whether the drug plan’s performance improved over time.


Helpful resources:

Other Notes on Our Rankings and Calculations

Government 5-star quality ratings are sourced from Our rankings are based on calculations of the average Overall Star Rating of Medicare Part D prescription drug plans for each insurance carrier within a particular State. Only standalone Medicare Part D plans are considered for our calculations. We do not consider Medicare Advantage, special needs plans (SNP), special eligibility or cost savings plans. We also do not consider new plans which do not yet have a 5-star quality rating. Counts for the number of plans within each State are based on unique Plan ID.

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