Centers for Medicare & Medicaid Services (CMS) Contact Information

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Need help with Medicare, Medicaid, Health Insurance Marketplace coverage, enrollment, a denied claim, a complaint or a medical bill? The correct contact depends on the program. The Centers for Medicare & Medicaid Services (CMS) oversees major federal health programs, but CMS headquarters does not manage every beneficiary account, state Medicaid case or private health-plan claim.

Use the CMS contact information and routing guide below to reach the department responsible for your question.

CMS Contact Information and Phone Numbers

Choose the correct support route:

  • Original Medicare coverage, claims or general Medicare questions: Call 1-800-MEDICARE.
  • Medicare Advantage or Part D plan: Call the member-service number on the plan identification card.
  • Enroll in Medicare Part A or Part B, change an address or apply for Extra Help: Contact Social Security.
  • Medicaid or CHIP application, eligibility, card, benefits or claim: Contact the member’s state Medicaid agency.
  • HealthCare.gov application, enrollment or Marketplace account: Contact the Marketplace Call Center.
  • Unexpected or potentially prohibited medical bill: Contact the No Surprises Help Desk.
  • NPI application or NPPES record: Contact the NPI Enumerator.
  • CMS policy, technical assistance or agency question: Use the CMS general number or official CMS contact page.

Protect your medical and personal information. Do not publish your Medicare number, Medicaid ID, Social Security number, date of birth, claim number, medical record, diagnosis, payment information or copies of health documents in a public review. Caller ID can be spoofed. If an unexpected caller asks for sensitive information, end the call and contact the appropriate agency through an official .gov website or a verified number listed on your card.

CMS, Medicare, Medicaid and the Marketplace Are Different

CMS is a federal agency within the U.S. Department of Health and Human Services. It oversees Medicare, works with states on Medicaid and CHIP, and administers federal Marketplace functions. However, different organizations handle individual cases:

  • Medicare provides federal health coverage for eligible older adults and certain younger people with disabilities or qualifying conditions.
  • Medicaid and CHIP are administered by individual states under federal requirements.
  • The Health Insurance Marketplace helps eligible consumers apply for and enroll in health plans through HealthCare.gov or a state-based Marketplace.
  • Social Security handles many Medicare Part A and Part B enrollment matters.
  • Private health plans handle their own member accounts, claims, provider networks, prior authorizations, appeals and plan benefits.

Medicare Customer Service

People with Medicare can call 1-800-MEDICARE / 1-800-633-4227. TTY users can call 1-877-486-2048. Medicare lists telephone representatives and live chat as available 24 hours a day, seven days a week, except some federal holidays.

Medicare can help with:

  • Original Medicare coverage questions
  • Processed claims and Medicare Summary Notices
  • Medicare cards and account questions
  • General plan information
  • Complaints about Medicare health or drug plans
  • Finding official Medicare resources
  • Reporting suspected Medicare fraud

Visit Medicare’s official contact page to call, start a live chat or locate personalized counseling.

If the question involves a Medicare Advantage, Medicare Part D or Medicare Supplement plan, call the number on the member’s current plan card. The plan—not CMS headquarters—normally handles plan-specific claims, benefits, provider networks, prescriptions and prior authorizations.

Medicare Enrollment and Social Security

Contact the Social Security Administration to enroll in Medicare Part A or Part B, change an address, apply for Extra Help with Medicare drug costs or resolve certain citizenship and residency questions.

Medicaid and CHIP Help

Medicaid and the Children’s Health Insurance Program are administered by states. Contact the appropriate state agency to:

  • Apply for Medicaid or CHIP
  • Check eligibility or application status
  • Request a replacement Medicaid card
  • Ask about covered benefits
  • Check a Medicaid claim
  • Find a participating health care provider
  • Report an address or household change
  • File a state Medicaid appeal or complaint

Use the official state Medicaid and CHIP contact directory. CMS headquarters can address federal policy, technical-assistance and program questions, but it generally cannot decide an individual state Medicaid application.

Health Insurance Marketplace Help

For HealthCare.gov applications, enrollment, eligibility notices, account access or Marketplace coverage, contact the Marketplace Call Center:

HealthCare.gov does not accept questions or application documents by ordinary email. Use the official Marketplace account, document-upload process or Call Center. After enrollment, contact the insurance company directly about premium payments, identification cards, provider networks, claims and plan benefits.

Medical Billing and No Surprises Act Help

Call the No Surprises Help Desk at 1-800-985-3059 for questions about unexpected medical bills and federal No Surprises Act protections. The Help Desk can also assist with submitting a complaint.

The Help Desk can explain federal billing protections and direct consumers to other resources. It cannot provide medical advice, legal representation or financial assistance.

Medicare Complaints and Appeals

A complaint and an appeal are not the same:

  • Complaint or grievance: A concern about service quality, delays, customer service, access or treatment by a plan or provider.
  • Appeal: A request to reconsider a decision not to cover or pay for an item, service or prescription, or a decision to reduce or end coverage.

Review the decision notice before taking action. It should identify the reason for the decision, the correct submission method and the deadline. Do not send a time-sensitive appeal to CMS headquarters unless the official notice specifically instructs you to do so.

CMS Provider and NPI Support

Health care providers should use provider-specific support instead of beneficiary customer service.

Medicare Administrative Contractors generally handle Medicare Fee-for-Service provider claims, billing, enrollment and jurisdiction-specific questions. Providers should not call 1-800-MEDICARE for routine provider billing support.

Report Medicare, Medicaid or HHS Fraud

For suspected fraud, waste or abuse involving Medicare, Medicaid or another HHS program, contact the HHS Office of Inspector General:

People with Original Medicare can also report questionable claims through 1-800-MEDICARE. Medicare Advantage and Part D members should review their plan’s fraud-reporting information.

CMS Headquarters and Regional Offices

CMS headquarters:
Centers for Medicare & Medicaid Services
7500 Security Boulevard
Baltimore, MD 21244

CMS also maintains regional offices that work with beneficiaries, providers, state governments, contractors and community organizations. Visit the CMS regional office directory for current regions and contact information.

Do not mail claims, medical records, applications or time-sensitive appeals to the headquarters address unless official instructions for the specific program direct you there.

Information to Gather Before Contacting Support

  • The program involved: Medicare, Medicaid, CHIP, Marketplace or another CMS program
  • The state where the beneficiary lives
  • The current health-plan identification card
  • The date and description of the problem
  • A claim, application, appeal or complaint reference number
  • The provider, facility or plan involved
  • The relevant notice, bill or explanation of benefits
  • Previous call dates and case numbers
  • The resolution being requested

Share sensitive information only through an official secure portal, verified telephone call or submission method identified by the responsible agency or health plan.

CMS Contact Information FAQs

What is the CMS customer service phone number?

The CMS general toll-free number is 1-877-267-2323. The correct number for an individual issue may instead be Medicare, a state Medicaid agency, HealthCare.gov, Social Security or the person’s health plan.

What is the phone number for Medicare?

Call 1-800-MEDICARE / 1-800-633-4227. TTY users can call 1-877-486-2048.

Is Medicare customer service available 24 hours?

Medicare lists telephone representatives and live chat as available 24 hours a day, seven days a week, except some federal holidays.

Does CMS handle Medicaid applications?

Individual states administer Medicaid and CHIP applications, eligibility, benefits and member services. Use Medicaid.gov’s state contact directory to locate the correct agency.

Who handles Medicare Part A and Part B enrollment?

The Social Security Administration handles many Medicare Part A and Part B enrollment matters. Call 1-800-772-1213 or use SSA.gov.

Who should I call about a HealthCare.gov application?

Call the Marketplace Call Center at 1-800-318-2596. TTY users can call 1-855-889-4325.

Who should I call about an unexpected medical bill?

Call the No Surprises Help Desk at 1-800-985-3059 to ask whether federal surprise-billing protections may apply or to receive help submitting a complaint.

Can CustomerServiceNumbers.com access my Medicare or Medicaid account?

No. CustomerServiceNumbers.com is an independent consumer-information and review website. It cannot access government records, determine eligibility, change coverage, view claims, file appeals or resolve individual benefit decisions.

Related Customer Service Resources

If the issue involves a private Medicare Advantage, Part D, Medicaid managed-care or Marketplace health plan, call the number on the member identification card. Additional plan-specific information is available on these CSN pages:

CMS Reviews and Complaints

There are currently no published CMS visitor reviews on this page. If you contacted CMS, Medicare, Medicaid, HealthCare.gov, Social Security or the No Surprises Help Desk, you may leave a review describing the department contacted, the reason for the contact, the approximate wait time and whether the issue was resolved.

Why Trust CustomerServiceNumbers.com?

CustomerServiceNumbers.com has helped consumers locate customer service phone numbers and support information since 2004. CSN is an independent consumer-help and review website. It is not owned by, affiliated with or operated by CMS, Medicare, Medicaid, HealthCare.gov, the U.S. Department of Health and Human Services or any health plan listed on this page.

Contact details are provided to help readers locate the appropriate official support route. Always verify coverage, eligibility, claims, appeals, deadlines, benefits and medical-billing requirements with the responsible government agency, state program or health plan.

Share Your Experience

Have you contacted CMS or one of the programs listed above? Share which department you contacted, whether the routing information was clear, how long you waited and whether you received a useful response. Specific, privacy-safe reviews can help other readers choose the correct support route.

Privacy reminder: Do not include Medicare numbers, Medicaid IDs, Social Security numbers, dates of birth, medical information, diagnoses, claim numbers, application numbers, financial details, addresses, telephone numbers, email addresses, appeal documents or private screenshots in a public review.

Disclaimer: This page provides general contact information and is not medical, legal, insurance or eligibility advice. CustomerServiceNumbers.com cannot determine coverage, benefits, eligibility or appeal outcomes. For medical advice, contact a qualified health professional. For a medical emergency, call 911.

Page Update Note: This page was reviewed on August 14, 2026. It provides current contact routes for CMS headquarters, Medicare, Medicaid and CHIP, the Health Insurance Marketplace, Social Security, medical-billing help, provider support and fraud reporting.

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