Medicare in Missouri: 2026 Plans, Costs, and Enrollment Guide

Missouri Medicare Snapshot

Missouri offers one of the most plan-dense MA markets in the country relative to its population — 157 Medicare Advantage plans from 14 carriers for 2026 (CMS CY2026 Landscape), with availability across all 115 Missouri county-equivalents (114 counties + the independent City of St. Louis). The Missouri Medigap market uses standard federal plan letters with attained-age pricing and is governed by the Missouri Medigap Anniversary Rule (§376.684 RSMo) — a 60-day no-underwriting carrier-switch window each year around your policy anniversary date.

The average consolidated MA premium is $8.56/month — one of the lower state averages nationally, reflecting a large share of zero-premium plans. The standard Medicare Part B premium is $202.90/month in 2026. The top carriers are Humana (35 plans), Aetna Medicare (34), and UnitedHealthcare (32).

Plan Types Available in Missouri

Medicare Advantage (Part C)

In Missouri, 157 MA plans are available for 2026 from 14 carriers (CMS CY2026 Landscape). The largest plan-type categories are HMO-POS (38), PPO (36), HMO (28), HMO D-SNP (16), and HMO C-SNP (8); a number of additional MA plans fall outside the top categories.

County-level plan counts range from 80 MA plans in the St. Louis area (the CMS Landscape extract used by TPP combines counts in the St. Louis area; verify your specific county/city via our county lookup) down to 18 plans in Dunklin County. Top carriers by plan count: Humana (35 plans), Aetna Medicare (34 plans), and UnitedHealthcare (32 plans). Average star rating is 3.75.

Medigap (Medicare Supplement)

Missouri uses the standard federal Medigap plan letters (A, B, C, D, F, G, K, L, M, N, plus HDG and HDF). 22 carriers offer Plan G in Missouri in the TPP rate database (CY2026, non-tobacco, ages 65–85). Plans C, F, and High-Deductible Plan F (HDF) are closed to anyone who first became Medicare-eligible on or after January 1, 2020 (under MACRA 2015); beneficiaries who were Medicare-eligible before that date may still buy Plans C, F, or HDF from carriers that continue to offer them. High-Deductible Plan G (HDG) is the post-2020 high-deductible option and is offered by 13 carriers in Missouri.

Missouri Medigap rates use attained-age pricing — premiums increase as you age. Beneficiaries can use the Missouri Anniversary Rule to re-shop carriers each year (see the Missouri-Specific Medicare Rules section below). See our MA vs Medigap comparison →

Standalone Part D (Prescription Drug Plans)

Missouri is a single-state PDP region (CMS PDP Region 18). For 2026, there are 10 standalone PDP plans from 5 carriers in Missouri. Average total premium is $63.41/month (CMS CY2026 Landscape).

Costs in Missouri

Medicare Advantage Premiums

The average consolidated MA premium in Missouri is $8.56/month (CMS 2026 Medicare MA & Part D Landscape State-by-State Fact Sheet). The standard Medicare Part B premium is $202.90/month in 2026.

Medigap Premiums — Plan G and HDG

Missouri Medigap rates use attained-age pricing (premiums based on current age). Across the 22 Missouri Plan G carriers (non-tobacco, ages 65–85), Plan G monthly premiums in 2026 range from approximately $188 to $768/month (TPP rate database, CY2026).

High-Deductible Plan G (HDG) is offered by 13 Missouri carriers; premiums range from approximately $187 to $714/month (TPP rate database, CY2026, non-tobacco, ages 65–85). HDG works well for beneficiaries who want catastrophic protection at a lower monthly cost and can absorb the $2,950 annual deductible (2026 CMS-published figure for HDG/HDF).

Part D Costs and the LIS Benchmark

For 2026, Missouri (PDP Region 18 — single-state) Part D premiums average $63.41/month across 10 standalone PDP plans (CMS CY2026 Landscape). The CMS Low Income Subsidy (LIS / Extra Help) benchmark premium for Region 18 is $43.03/month (CMS CY2026 Regional Rates and Benchmarks).

Missouri-Specific Medicare Rules

Missouri Medigap Anniversary Rule

Missouri is currently the only U.S. state with a Medigap Anniversary Rule, codified at §376.684 RSMo. The rule applies to beneficiaries who already have a Missouri Medigap policy:

• Window:30 days before through 30 days after your policy's annual anniversary date (the date your policy first became effective) — a total 60-day window each year.
• Allowed switch: You can change to the same lettered Medigap plan offered by a different carrier— for example, from Carrier A's Plan G to Carrier B's Plan G — without medical underwriting.
• Restrictions: Changing to a different plan letter (e.g., Plan G to Plan N, or Plan N to Plan G) generally requires medical underwriting and is not protected by the Anniversary Rule.
• Eligibility: You must already hold a Missouri Medigap policy to use the rule. Beneficiaries who currently have Medicare Advantage or Original Medicare without a Medigap policy cannot use the Anniversary Rule to enroll in a new Medigap plan without underwriting.

The Anniversary Rule is distinct from state "Birthday Rule" protections (which key off the policyholder's birthday). In Missouri, the window keys off the policy anniversary date — different policies bought at different times will have different windows.

Medicare Savings Programs (MSPs)

Missouri offers Medicare Savings Programs (MSPs) through MO HealthNet (Missouri's Medicaid program):

• QMB (Qualified Medicare Beneficiary): Covers Part A and Part B premiums, deductibles, and cost-sharing.
• SLMB (Specified Low-Income Medicare Beneficiary): Covers Part B premiums only.
• QI (Qualifying Individual): Also covers Part B premiums; subject to annual appropriations.

Apply through MO HealthNet or contact CLAIM (1-800-390-3330) for free enrollment assistance. MSP enrollment also automatically qualifies you for Extra Help / LIS on Part D. Learn more about MSPs →

Missouri CLAIM (State Health Insurance Assistance Program)

Missouri CLAIM (Community Leaders Assisting the Insured of Missouri) is Missouri's federally designated State Health Insurance Assistance Program (SHIP), administered by the Missouri Department of Health and Senior Services. CLAIM provides free, unbiased Medicare counseling statewide through trained volunteers.

Phone: 1-800-390-3330
Website: health.mo.gov/seniors/claim

Enrolling in Medicare in Missouri

Standard Enrollment Periods

• Initial Enrollment Period (IEP): 7-month window centered on your 65th birthday month. Enroll at ssa.gov or call 1-800-772-1213.
• Annual Election Period (AEP): October 15 – December 7 each year.
• Medicare Advantage Open Enrollment Period (OEP): January 1 – March 31.
• Missouri Anniversary Rule (Medigap): 30 days before + 30 days after your policy anniversary date — same lettered plan with a different carrier, no underwriting.
• Federal 6-month Medigap OEP: Starts when you are 65+ and enrolled in Part B; first-time Medigap guaranteed issue.
• Special Enrollment Periods (SEPs): Learn more →

Missouri CLAIM Counseling

Contact Missouri CLAIM at 1-800-390-3330 for free one-on-one Medicare guidance statewide.

Frequently Asked Questions