Medicare in Illinois

Medicare enrollment in Illinois

As of February 2026, there were 2,470,482 Medicare beneficiaries in Illinois.¹

Most beneficiaries become eligible for Medicare enrollment when they turn 65. But after receiving Social Security disability benefits for two years, a person will become eligible for Medicare even if they’re under 65, and Medicare eligibility is also triggered if a person has been diagnosed with amyotrophic lateral sclerosis (ALS) or end-stage renal disease (ESRD). Nationwide, about 9% of people enrolled in Medicare are under 65;² similarly in Illinois, almost 9% of Medicare beneficiaries are under 65.¹

• Read about Medicare’s open enrollment period and other important enrollment deadlines.
• Learn how Illinois’s Medicaid program can provide assistance to Medicare beneficiaries with limited income and assets.

Medicare Advantage plan availability and enrollment in Illinois

There are Medicare Advantage plans for sale throughout Illinois, with 2026 plan availability ranging from 14 plans to over 50 plans, depending on the county. The average Medicare beneficiary in Illinois can choose from among 45 Medicare Advantage plans in 2026.³

As of February 2026, 44% of Medicare beneficiaries in Illinois were enrolled in Medicare Advantage plans¹

Learn more about Medicare Advantage, Medicare’s annual open enrollment period, and the Medicare Advantage open enrollment period.

Sources: Medicare Advantage 2026 Spotlight: A First Look at Plan Offerings, KFF.org, Dec. 9, 2025; Fact Sheet: Medicare Open Enrollment for 2026, Centers for Medicare & Medicaid Services. Sep. 26, 2025

Medicare supplement (Medigap) plan availability in Illinois

According to AHIP, 752,795 Illinois Medicare beneficiaries were enrolled in Medigap plans (also known as Medicare Supplement insurance) in 2023,⁴ to supplement their Original Medicare coverage.

Federal rules provide a six-month guaranteed-issue enrollment window for Medigap, starting when a person is at least 65 and enrolled in Medicare Part A and Medicare Part B. Federal rules do not provide annual guaranteed-issue enrollment or plan change opportunities, and federal rules also do not guarantee access to Medigap for Medicare beneficiaries under the age of 65.

But Illinois has stronger consumer protections in this area than most other states.

Birthday rule

In 2021, Illinois enacted legislation that created a new Medicare Supplement Annual Open Enrollment Period (effective as of 2022)⁵ The annual enrollment opportunity is fairly limited, but it does still go beyond federal rules. Illinois Medigap enrollees between the ages of 65 and 75 have an annual window during which they can switch to a different Medigap plan, offered by their current Medigap insurer (or an affiliate of their current insurer),⁶ as long as the plan offers equal or lesser benefits (so a person could switch from Plan F to Plan G, but not from Plan A to Plan G, for example).

The window starts on the beneficiary’s birthday, and lasts for 45 days.⁷ (Several other states have developed similar “birthday rule” Medigap plan change opportunities, but the Illinois version is among the more limited, since it doesn’t apply to enrollees over the age of 75.)

Guaranteed issue coverage from BCBSIL

And Illinois residents who are 65 or older can enroll year-round into certain guaranteed-issue plans offered by Blue Cross and Blue Shield of Illinois (BCBSIL)⁷ (Plans A, G, and N are available, plus some additional variations of those plans).⁸

Guaranteed-issue coverage for beneficiaries under 65

Illinois Medicare beneficiaries who are under 65 have a six-month guaranteed-issue window during which they can enroll in any Medigap plan sold in their area. However, the premiums can be higher than they would be for a 65-year-old enrollee. So when the person turns 65, they can utilize the federally required Medigap enrollment window to switch plans and/or obtain the age-65 premiums.⁹

Annual enrollment opportunity with BCBSIL for beneficiaries under 65

Additionally, if an Illinois Medicare beneficiary is under 65 and didn’t enroll in Medigap during their initial enrollment window, they have an annual opportunity to enroll in guaranteed issue coverage offered by BCBSIL, between October 15 and December 7.⁷

Learn how Medigap plans are regulated and standardized.

Medicare Part D plan availability and enrollment in Illinois

Insurers in Illinois are offering 12 stand-alone Medicare Part D plans for sale in 2026, with premiums that start at $0/month.¹⁰

As of February 2026, more than 2 million Illinois Medicare beneficiaries had Medicare Part D coverage.¹ About 51% of them had stand-alone Medicare Part D plans, while the other 49% had Medicare Advantage plans that included Part D coverage.¹¹

Learn how Medicare Part D prescription drug coverage works, what it pays for, how and when to enroll.

Source: Fact Sheet: Medicare Open Enrollment for 2026, Centers for Medicare & Medicaid Services. Sep. 26, 2025

Resources for Medicare beneficiaries in Illinois

Have questions about Medicare enrollment or Medicare eligibility in Illinois?

• You can contact the Illinois Senior Health Insurance Program with questions related to Medicare coverage in Illinois.
• The Illinois Department on Aging has an excellent resource for Illinois residents who are shopping for Medigap plans. Premiums vary by location, so there are three separate guides: Chicago Area, North-Central Area, and Southern Area.
• Illinois has a helpful handbook for state employees who are transitioning to Medicare.
• The Medicare Rights Center website provides helpful information geared to Medicare beneficiaries, caregivers, and professionals.