Best Medicare Supplement Plans in Illinois (2026)

MedMutual Protect is the best Medicare Supplement company in Illinois for most 65-year-old enrollees. It prices Plans F, G and N lower than any other Illinois insurer. Plan G covers 49% of Illinois Medigap members, the highest share of any plan type.

Each other plan type has a different price leader. USAA prices Plan A at $121 monthly, $105 below the state average. Transamerica prices Plans K and L lowest at $96 and $143 monthly. COUNTRY Financial prices Plans C and D lowest at $193 and $185 monthly.

The monthly rate is only one variable. MedMutual's premiums rise each year under attained-age pricing, which means the rate increases annually as you age. Transamerica locks your rate at enrollment for all 10 plan types under issue-age pricing. Seniors planning to hold a Medigap policy 10 years or more should request long-term rate projections before enrolling.

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*These rates reflect Medigap premiums for 65-year-olds.

Plan G covers all Original Medicare cost-sharing except the annual Part B deductible, which costs $283 in 2026. Plan G accounts for approximately 49% of Illinois Medigap members per NAIC, the highest share of any plan type. MedMutual prices Plan G at $144 monthly, $109 below the state average. A 65-year-old who chooses MedMutual over the state average insurer saves $1,308 annually.

Plan N covers most Original Medicare cost-sharing with copays of up to $20 at most doctor visits and up to $50 at the emergency room. Plan N doesn't cover the Part B deductible or Part B excess charges. Plan N accounts for approximately 8% of Illinois Medigap members and suits seniors in good health who visit primary care doctors regularly and have few specialist visits.

Plan F covers every Original Medicare cost including the Part B deductible and Part B excess charges, which are fees certain doctors bill above Medicare's approved rate. Residents who became Medicare-eligible on or after January 1, 2020, cannot enroll in Plan F and should consider Plan G as the most comprehensive alternative available to them. Plan F accounts for approximately 40% of Illinois Medigap members.

MedMutual prices Plan F at $164 monthly, the lowest rate in Illinois and $155 below the state average. Illinois seniors eligible to choose between Plan G and Plan F save $792 annually in premiums with Plan G at state average rates. Plan G's only uncovered cost is the $283 Part B deductible in 2026, so Plan G enrollees who meet the deductible still save $509 for the year compared to Plan F policyholders.

Plan type determines most of what you pay for Illinois Medigap coverage. Plan K, the least expensive on average at $117 monthly, covers 50% of most Medicare out-of-pocket costs. Plan F, the most expensive on average at $319 monthly, covers every Medicare cost including the Part B deductible. Lower premiums mean more out-of-pocket exposure when you actually need care.

For seniors choosing between Plans G and N, Plan G costs $53 monthly more on average. That premium covers Plan G's full Part B coinsurance coverage, which Plan N replaces with copays of up to $20 per doctor visit. Seniors who rarely see specialists pay less with Plan N over a full year. Seniors with ongoing conditions and frequent doctor visits pay less with Plan G once copays add up.

Coverage needs vary across Illinois seniors. Use the filters below to compare rates by plan type and age. Because plans are federally standardized, the most important column is the monthly premium. A lower rate for the same plan type means the same coverage for less money.

Every Illinois Medicare Supplement plan is federally standardized, so Plan G from one insurer covers exactly the same services as Plan G from any other. The only differences between insurers offering the same plan are the monthly premium and how that premium changes each year. Choose your plan type based on how often you use health care and what you can afford monthly, then compare what each insurer charges for that plan.

Cost, service quality and company reliability are the only meaningful differences when choosing a Medicare Supplement insurer in Illinois. Benefits are identical across all companies for the same plan type.

Illinois residents comparing Medigap plans can access these resources:   

• The Senior Health Insurance Program (SHIP): Provides free, one-on-one Medicare counseling through trained volunteers and certified counselors. Sessions are confidential and cover Medigap plans, Medicare Advantage and Part D prescription drugs. To reach a SHIP counselor, call the Senior HelpLine at 1-800-252-8966 (TTY 1-888-206-1327) or email aging.ship@illinois.gov.
• The Illinois Department of Insurance Consumer Services: Handles Medigap complaints. File online or call the Consumer Assistance Hotline at 866-445-5364. Illinois law gives insurers 21 days to respond after receiving a complaint. Written complaints go to 320 W. Washington Street, Springfield, IL 62767. The Chicago office is at 115 S. LaSalle Street, 13th Floor, (312) 814-2420.
• Illinois Area Agencies on Aging: Coordinates senior services through 13 regional agencies covering all 102 counties. Call the Senior HelpLine at 1-800-252-8966 to reach the agency in your area.
• Medicare.gov: Offers a Plan Finder tool where you can enter your ZIP code to compare Medigap policies sold in Illinois side by side.

MoneyGeek collected rate data for all Illinois Medicare Supplement plans using the plan finder at Medicare.gov. Rates reflect quotes for a non-tobacco user in a Chicago-area ZIP code. Unless noted, all figures show premiums for 65-year-old enrollees. Rates were collected in May 2026.

We scored insurers across three categories to build each MoneyGeek rating out of 5 points.

• Affordability (50%): Insurers with the lowest monthly premiums score higher. Among Illinois Plan G providers, the monthly range across reviewed insurers spans $68, from MedMutual at $144 to USAA at $212. Cost differences this large make affordability the most important factor for most enrollees.
• Pricing style (20%): We scored pricing methods from most to least rate-stable, with Community Pricing weighted at 1.0 (most stable), Issue-Age Pricing at 0.8 and Attained Age Pricing at 0.6 (least stable). A community-rated plan with a slightly higher current premium can score above an attained-age plan when its long-term rate trajectory is more predictable.
• Plan availability (30%): Insurers offering more plan types score higher. We weighted Plan G, Plan F and Plan N more heavily because they cover approximately 97% of Illinois Medigap members per NAIC 2024 data. Transamerica is the only insurer on this page offering all 10 standardized plan types.