Key Takeaways
- FEHB and Medicare Part B offer distinct yet potentially complementary coverage options for federal employees and retirees.
- Understanding cost structures, coverage differences, and coordination rules is essential before making retirement healthcare decisions.
Many federal retirees are confused about how their longtime FEHB coverage interacts with Medicare Part B, especially since rules and options can affect both costs and care. This resource unpacks the major differences, similarities, and coordination between these two important health benefits.
What Is FEHB?
Overview of Federal Employees Health Benefits
The Federal Employees Health Benefits (FEHB) Program is the primary health insurance program for federal workers and retirees. Managed by the Office of Personnel Management (OPM), FEHB offers a wide range of plan types—such as fee-for-service and health maintenance organizations—that cover hospital, medical, and preventive services. As a federal employee or annuitant, you generally have access to annual open seasons to select your plan, and you can continue FEHB into retirement if you meet specific eligibility requirements.
Core features for retirees
For retirees, FEHB remains a robust healthcare option. You may keep your FEHB plan into retirement if you are entitled to a federal annuity and have been continuously enrolled (or covered as a family member) for the five years prior to retirement, or for the entire period of service if less than five years. FEHB continues providing inpatient and outpatient care coverage, preventive services, and catastrophic protection through out-of-pocket limits. Importantly, FEHB coverage extends to eligible family members and typically does not require Medicare enrollment to remain active in retirement, but decisions about pairing with Medicare Part B can affect costs and coverage.
What Is Medicare Part B?
Basics of Medicare Part B
Medicare Part B, administered by the Centers for Medicare & Medicaid Services (CMS), is a federal program that primarily serves people 65 and older and some younger individuals with disabilities. Part B pays for medically necessary outpatient care—including doctor visits, preventive services, lab work, outpatient surgeries, durable medical equipment, and home health care. Unlike hospital insurance (Part A, which is usually premium-free for most), Part B requires a monthly premium and helps fill coverage gaps in other plans, such as FEHB, especially in outpatient settings.
Enrollment process explained
Most people become eligible for Medicare at age 65. Enrollment in Part B is not automatic for federal retirees who are not receiving Social Security. There is a seven-month initial enrollment period: the three months before your 65th birthday, the month you turn 65, and the three months after. If you do not enroll during this window and are not covered by active employment insurance, you could face late enrollment penalties. Retirees may postpone Part B enrollment if they or their spouse have current employment-based coverage, such as FEHB based on active employment; however, timing the decision is important to avoid gaps or penalties.
How Do Coverage Rules Differ?
FEHB coverage in retirement
FEHB coverage remains comprehensive in retirement, even if you do not enroll in Medicare. FEHB plans typically cover hospitalization, doctor visits, preventive screenings, outpatient care, prescription drugs, mental health, and emergency services. Coverage terms, provider networks, and cost-sharing levels can differ depending on the specific plan you select. After retirement, you retain the same federal protections, such as inflation-indexed government contributions toward your premium and a cap on maximum out-of-pocket expenses.
Medicare Part B covered services
Medicare Part B primarily covers outpatient healthcare services, including visits to physicians, preventive screenings, X-rays, lab tests, outpatient surgeries, home health services, and durable medical equipment. Part B does not include most prescription drug costs, inpatient hospital stays (covered by Part A), or long-term care. Together with FEHB, Part B can provide nearly full coverage for most standard outpatient procedures, but some coverage areas may overlap or change billing processes once you enroll.
What Are the Cost Considerations?
Premium structures for each plan
FEHB plans have monthly premiums that participants share with the federal government. The government generally pays a set percentage of plan premiums while you cover the remainder. In retirement, you continue paying your share of the premium, deducted from your annuity or billed directly if your annuity is insufficient. Medicare Part B requires an independent monthly premium, calculated based on income brackets set by law, and paid directly or deducted from Social Security or federal retirement benefits. If you choose both FEHB and Part B, you will pay both premiums indefinitely, which can represent a significant monthly expense.
Typical out-of-pocket costs
With FEHB alone, your expenses might include deductibles, copayments, and coinsurance, outlined in your chosen plan’s schedule. A maximum annual out-of-pocket limit caps your cost exposure each year. Medicare Part B also has a deductible and coinsurance, typically 20% of the Medicare-approved amount for most doctor services after you meet the deductible. When you have both FEHB and Part B, your FEHB often pays secondary to Medicare, meaning your out-of-pocket costs may be reduced or eliminated for covered outpatient services, but you must weigh these potential savings against the cost of carrying both premiums.
How Does Coordination of Benefits Work?
Which pays first: FEHB or Part B?
Once you are retired and age 65 or older, and if you have both FEHB and Part B coverage, Medicare Part B generally pays first for eligible services, while FEHB processes claims as the secondary payer. If Medicare does not cover a particular service, then FEHB may cover it, subject to plan rules. If you are still employed (not just retired) and covered by FEHB due to current employment, FEHB pays first, and Medicare is generally secondary.
Impact on claims and billing
When Medicare pays first, it determines the allowed amount for covered services; then FEHB may cover some or all of the remaining costs, depending on your FEHB plan. This process can reduce your out-of-pocket liability for certain services. Claims are generally coordinated electronically, so you don’t have to file multiple forms, but confirm with all providers that they accept both Medicare and your FEHB plan to ensure seamless billing.
Do Retirees Need Both FEHB and Part B?
Rules and optional scenarios
Retirees are not required to enroll in Medicare Part B to retain FEHB coverage. Rules allow you to keep your FEHB plan for life as long as you remain eligible for your federal annuity and meet FEHB’s continuity requirements. Enrolling in Medicare Part B is optional, but some retirees find that having both plans provides more comprehensive coverage and reduced out-of-pocket expenses, especially for extensive outpatient care.
Factors to weigh before deciding
When considering whether to carry both, weigh the monthly premium costs of two plans against potential reductions in deductibles, coinsurance, and copayments, as well as broader provider access and fewer billing hurdles. Your anticipated medical needs, budget, and comfort with risk should inform your decision. Remember that your decision is not permanent: you can add Part B later (subject to certain rules), and you may change your FEHB plan during Open Season each year.
What If You Delay Medicare Enrollment?
Potential penalties and effects
If you delay enrolling in Medicare Part B past your initial eligibility period, and do not have current employment-based coverage, you may incur a permanent increase in your Part B premium for each 12-month period you were eligible but not enrolled. Delayed enrollment may also limit when you can sign up—usually during annual General Enrollment (January to March)—which could create coverage gaps.
Late enrollment exceptions
Exceptions apply if you or your spouse are covered by a group health plan based on current employment; you can safely delay Part B until coverage ends. Once that employment (not just FEHB coverage) ends, you have an eight-month Special Enrollment Period to enroll in Part B without penalty. Retirees already separated from service with only FEHB (not tied to active employment) typically don’t qualify for this exception, so review your situation before deciding to delay.
Common Questions About FEHB and Part B
How do prescription drug rules differ?
FEHB plans generally include prescription drug coverage, often comparable to or more comprehensive than the optional Medicare Part D coverage. Federal retirees are not required to enroll in Medicare drug plans if they keep FEHB, as FEHB drug coverage is considered “creditable.” This means you avoid late enrollment penalties for Part D.
Can you drop FEHB after enrolling in Part B?
You may cancel your FEHB coverage at any time, but reinstatement is generally not permitted except in limited circumstances, such as returning to federal service. Most retirees retain FEHB, using Medicare as either supplemental or primary depending on coordination rules. Dropping FEHB is rare because of its extensive coverage and federal premium sharing, but the option exists.
What changes after age 65?
At age 65, you become eligible for Medicare, but you don’t have to enroll in Part B to keep FEHB. However, coverage coordination—and potentially, your out-of-pocket costs—can change once Medicare becomes primary. Federal retirees often experience expanded provider access, changes in coinsurance rates, and billing procedures after enrolling in Medicare, but your FEHB protections and premium contributions remain in place as long as you’re eligible.
