Best Medicare Supplement Plans in Illinois (2026)

MedMutual Protect is the best Medicare Supplement company in Illinois for 65-year-olds who choose Plan G, F or N. It charges the lowest rates for all three, and its $144 Plan G is $109 a month below the $253 average. Its $144 Plan G is $109 a month below the $253 average.

Other plan types have different cheapest insurers. USAA's $121 Plan A is $105 below average but sold only to veterans, service members and their families. Transamerica is cheapest for Plans K and L, and COUNTRY Financial for Plans C and D.

MedMutual uses attained-age pricing, which raises premiums as you age. MedMutual's Plan G costs $144 at 65 and $180 at 75. Transamerica's issue-age pricing bases your premium on your age at purchase, so aging alone won't raise it. Seniors keeping Plan G past 75 should ask both insurers for rate projections.

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*Rates are for a 65-year-old non-tobacco user in a Chicago-area ZIP code, collected from Medicare.gov in May 2026.

MedMutual Protect has Illinois' lowest Plan G rate at $144 a month for a 65-year-old, $109 below the $253 Illinois average, or $1,308 a year. Plan G pays all Original Medicare cost-sharing except the Part B deductible, the $283 you pay in 2026 before Part B starts paying.

*Rates are for a 65-year-old non-tobacco user in a Chicago-area ZIP code, collected from Medicare.gov in May 2026. Savings compare each rate with the Illinois average for that plan type.

MedMutual Protect has Illinois' lowest Plan N rate at $101 a month for a 65-year-old, $99 below the $200 Illinois average. Plan N pays most Original Medicare cost-sharing but charges copays of up to $20 at most doctor visits and up to $50 for emergency room visits that don't lead to admission. It doesn't pay the $283 Part B deductible or Part B excess charges, which are fees some doctors bill above Medicare's approved amount. Against MedMutual's $144 Plan G, Plan N saves $516 a year, enough for 25 doctor visits at the $20 maximum copay, so it fits healthy seniors with fewer visits.

MedMutual Protect has Illinois' lowest Plan F rate at $164 a month at 65, $155 below the $319 Illinois average. Plan F pays all Original Medicare cost-sharing, including the Part B deductible and Part B excess charges. Only people eligible for Medicare before January 1, 2020, can buy it.

Plan G costs $66 a month less than Plan F at Illinois averages, or $792 a year, so it stays $509 cheaper after its $283 Part B deductible. At MedMutual, Plan F costs $240 a year more than Plan G, $43 less than the deductible, so seniors who meet it pay less with Plan F. These are age-65 rates, and anyone who qualified for Plan F by age is now at least 71, so compare plans at your age.

Illinois average Medigap rates range from $117 a month for Plan K to $319 for Plan F, a $202 difference. Plan G rates alone range from $144 at MedMutual to $276 at United American, $132 apart. Plan K's low premium comes with cost-sharing. It pays 50% of most costs until you hit its $8,000 out-of-pocket limit for 2026.

Plan G costs $53 a month more than Plan N at Illinois averages, or $636 a year. At Plan N's $20 maximum copay, that covers about 32 doctor visits, so seniors with fewer visits pay less with Plan N and frequent doctor users pay less with Plan G.

Each Illinois Medigap plan letter covers the same costs at every insurer, so State Farm's $124 Plan A buys the same coverage as Globe Life's $171 Plan A for $47 a month less. Every Plan A insurer listed uses attained-age pricing, so these rates rise as you age.

Each Illinois Medigap plan letter is federally standardized, so MedMutual's $144 Plan G covers the same services as USAA's $212 Plan G. Choose the plan type that matches how often you use care, then compare insurers' prices and pricing methods for that plan.

Every insurer's Plan G covers the same services, so Illinois Medigap insurers differ on price, pricing method, complaint record and extras.

Illinois' Senior Health Insurance Program (SHIP) and Department of Insurance offer free help before and after you buy a Medigap plan.

• The Senior Health Insurance Program (SHIP): Provides free, confidential one-on-one Medicare counseling on Medigap plans, Medicare Advantage and Part D drug plans. 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 online or through the Consumer Assistance Hotline at 866-445-5364, and Illinois law gives insurers 21 days to respond. Mail written complaints to 320 W. Washington Street, Springfield, IL 62767, or visit the Chicago office at 115 S. LaSalle Street, 13th Floor, (312) 814-2420.
• Illinois Area Agencies on Aging: 13 regional agencies coordinate senior services across all 102 counties, reachable through the same Senior HelpLine at 1-800-252-8966.
• Medicare.gov: Its Medigap policy search compares Illinois Medigap policies by ZIP code and is the tool MoneyGeek used to collect this page's May 2026 rates.

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 we reviewed, monthly rates range from $144 at MedMutual to $276 at United American, a $132 difference. Differences this large are why affordability carries half the score.
• Pricing style (20%): We scored pricing methods from most to least rate-stable. Community pricing, where everyone pays the same premium regardless of age, scores 1.0. Issue-age pricing, based on your age at purchase, scores 0.8, and attained-age pricing, which rises as you age, scores 0.6. 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. Transamerica is the only insurer on this page offering all 10 standardized plan types.