Enrolling as a Provider with Medicare MCOs

Medicare Advantage (MCO) provider enrollment is the process of joining a plan’s network so you can see their members as an in-network provider. Unlike Original Medicare enrollment (one enrollment covers all Original Medicare patients), MCO enrollment must be done separately for each plan you want to join.

This page covers the enrollment mechanics for individual providers and groups.

Prerequisites before you start

1. Active Original Medicare enrollment Most MCO plans require active Original Medicare billing privileges before they’ll credential you. Complete your CMS-855I (individual) or CMS-855B (organization) enrollment first.

2. Current CAQH ProView profile Nearly all major MCO plans use CAQH ProView for primary source verification. Register at proview.caqh.org and complete your profile before applying to any plan. The profile must be re-attested every 120 days.

3. Current NPI Your Type 1 NPI (individual) or Type 2 NPI (organization) must be active and accurate in NPPES.

4. Current licenses and insurance All state licenses current. Malpractice insurance active with limits meeting each plan’s minimums (typically $1M/$3M for most specialties, but verify).

The enrollment process: step by step

Step 1: Identify which plans to join

Before applying, identify 3–5 priority plans in your market. Methods:

• Check your existing patients’ insurance cards
• Run eligibility verification on your current patient panel
• Ask your referral sources which plans they use most
• Check CMS’s public Medicare Advantage enrollment data by county

Step 2: Contact each plan

Large national plans (UHC, Humana, Aetna, Anthem/BCBS):

• Use their online provider portal
• Most have a “Join Our Network” or “Provider Credentialing” page
• Search: “[Plan name] become a provider” or “[Plan name] provider credentialing”

Regional plans:

• May require a phone call to their provider relations department first
• They’ll send credentialing packets or guide you to an online application

Step 3: Complete CAQH authorization for each plan

After contacting each plan:

1. Log in to your CAQH ProView account
2. Find the “Authorizations” section
3. Authorize each plan to access your CAQH data
4. Plans pull primary source verification directly from CAQH once authorized

This is the core of MCO credentialing for most plans — authorizing CAQH access, answering supplementary questions, and submitting any non-CAQH documentation.

Step 4: Complete plan-specific applications

Even with CAQH, most plans have additional steps:

Supplementary questions:

• Plan-specific questions about practice patterns, hospital affiliations, specialty certifications
• Acknowledgment of plan policies and credentialing criteria

Additional documentation (plan-specific):

• DEA registration (if prescribing)
• Board certification certificate
• Hospital privilege documentation (for hospital-based providers)
• W-9 (for tax purposes)
• Voided check or ACH authorization for payment

Step 5: Credentialing committee review

Plans conduct a credentialing committee review — typically monthly for most plans. Your application enters the queue after CAQH verification is complete and all documentation is received.

Common reasons for credentialing delay:

• CAQH attestation expired
• Malpractice coverage gap in history
• State license in question
• Undisclosed adverse action

If your credentialing is stalled, contact the plan’s credentialing department directly. Ask for the specific reason.

Step 6: Contract execution

After credentialing approval, the plan sends you a participation agreement. This is a contract with fee schedule, billing requirements, and terms. Contracting guide →

Review carefully before signing. Execute both parties’ signatures.

Step 7: Effective date and activation

Your participation agreement specifies your effective date. After that date:

• You’re listed in the plan’s provider directory
• You can see the plan’s members as in-network
• Claims submit to the plan, not to your MAC

Group practice MCO enrollment

For groups, the enrollment structure is layered:

Organization-level credentialing: The group practice files a group application (or a rosters application under the group’s Type 2 NPI) and negotiates a group contract.

Individual provider credentialing: Each provider within the group is credentialed individually. The group contract governs rates and terms; individual credentialing confirms each provider’s qualifications.

Roster management: When adding new providers to a group that’s already in-network with MCOs, you need to:

• Complete credentialing for the new provider with each plan
• Add the provider to the group’s roster with each plan
• Confirm the plan has processed the roster addition before the provider sees plan patients

Allow 30–60 days for roster additions.

⚠️ Risk flags

⚠️ Seeing plan patients before your effective date. You’re out-of-network until your effective date. If a patient presents with an MCO card for a plan whose effective date hasn’t passed, check with your biller before scheduling.

⚠️ CAQH attestation lapse causes credentialing suspension. Plans typically deactivate providers whose CAQH attestation is more than 120 days stale. Set a calendar alert. Every 4 months, log in and re-attest.

⚠️ Different plans, different rules. Don’t assume your process with Plan A works for Plan B. Each plan has its own credentialing criteria, documentation requirements, and billing requirements. Treat each as a separate workflow.

⚠️ Provider directory lags. Even after your effective date, plan provider directories may take 2–4 weeks to update. Patients calling the plan to verify your participation may get inaccurate information during the lag. If this is causing access problems, contact the plan’s provider relations team.

Timeline to in-network status

Related pages

• MCO Overview
• Contracting with Medicare Advantage Plans
• CMS-10114 — Medicare Advantage Provider Form
• MCO vs. Original Medicare

Questions about the MCO enrollment process? Ask Mae →