Illinois Medicare Part B: 6 Key Rules for Therapists
Illinois Medicare Part B pays for outpatient mental health care, but only if you enroll, bill the right contractor and file on time. This guide covers the basics for Illinois therapists and psychiatrists. Status is current as of October 17, 2026. This is operational guidance, not legal advice.
1. Who processes Illinois Medicare Part B claims
Medicare Part B is the part of Original Medicare that covers outpatient medical and mental health services. In Illinois, claims go to a Medicare Administrative Contractor (MAC). The Centers for Medicare & Medicaid Services (CMS) lists National Government Services, Inc. as the Jurisdiction 6 (J6) contractor for Part A and Part B in Illinois, Minnesota and Wisconsin. CMS shows the contract ending around July 2027, so check for changes.
Medicare Advantage plans are different. Those are private plans, and you bill them under their own rules. See our guide on in-network vs out-of-network billing.
If you are new to Illinois Medicare Part B, confirm which contractor handles your enrollment and claims before anything else. Sending a claim to the wrong place only delays payment.
2. Who can bill Medicare for mental health
CMS lists these practitioners in its Medicare Mental Health booklet (MLN1986542, March 2026):
- Physicians, including psychiatrists
- Clinical psychologists
- Clinical social workers
- Marriage and family therapists and mental health counselors
- Nurse practitioners, physician assistants and clinical nurse specialists
Clinical social workers, marriage and family therapists and mental health counselors must accept assignment. Assignment means you accept the Medicare-approved amount as payment in full. Payment for those three groups is 75% of the physician fee schedule amount for clinical psychologists, per the booklet.
3. How to enroll with Illinois Medicare Part B
Start with a National Provider Identifier (NPI) from NPPES. Then apply through PECOS, the Provider Enrollment, Chain and Ownership System, or on paper. Individuals use the CMS-855I form. The name, Social Security number and tax ID on the application must match your NPI record. Describe the process to clients, but do not promise a start date. Group enrollment and reassignment of benefits have extra steps. Our credentialing page explains how enrollment fits with commercial payers.
4. Telehealth under Illinois Medicare Part B
Mental health telehealth is permanent under Medicare, per CMS. The patient may be at home, and audio-only is allowed in some cases. The HHS telehealth policy page (updated February 5, 2026) says the in-person visit requirement for mental health telehealth is waived through December 31, 2027. That is a temporary waiver, not a permanent change.
5. Timely filing, assignment and opt-out
Medicare denies claims filed more than 12 months, or one calendar year, after the date of service. The Medicare Claims Processing Manual, Chapter 1 (Section 70.4) sets the rule, and Section 70.7 lists limited exceptions. File early. Do not count on an exception.
Some practitioners opt out of Medicare. Under a private contract, the patient pays you directly. A contractor opt-out guide says the opt-out lasts two years and renews automatically. Talk to counsel before you opt out.
6. Incident-to billing for behavioral health
Incident-to means billing a team member’s service under a physician or other eligible practitioner. CMS says incident-to behavioral health services can be furnished under general supervision. Rules still apply, so confirm your setup before you bill. Check our Billing Terms Glossary for unfamiliar terms.
Practical tips for Illinois Medicare Part B
Many practices ask whether Illinois Medicare Part B is worth the paperwork. The answer depends on your patient mix, so run the numbers first. Enroll before you see your first Medicare patient. Keep your NPI and enrollment records current. Set a reminder at 90 days after each date of service so nothing nears the 12-month limit. Build a checklist for Illinois Medicare Part B claims and review it each quarter. Track Medicare separately from commercial payers, using the insurance companies contact page for payer lines.
Medicare rules change, and each payer reads them a little differently. Keep a short file of your enrollment confirmation, your assignment choice and your telehealth documentation. If a claim is denied, read the remittance codes before you resubmit.
Do not wait months to follow up. A claim sitting in a pending status is easy to lose. Call, write down the reference number, and follow up in writing. If a payer keeps missing deadlines, a state complaint may help. Medicaid and Medicare claims follow separate rules, so keep those in their own workflow.
Where MCM South helps
MCM South Medical Billing Service, LLC bills for psychotherapists and psychiatrists in ten states: Georgia (GA), Massachusetts (MA), Connecticut (CT), Texas (TX), Florida (FL), New York (NY), Colorado (CO), Tennessee (TN), North Carolina (NC) and Illinois (IL). We handle claims, denials and follow-up so you can focus on patients. Get a Free Quote or Schedule a Consultation.
Keep learning: Browse the Resources hub, the State & Regional Billing Guides and our practice management tips.
More from MCM South: Illinois insurance companies contact guide; Medicare Part B glossary entry; MAC jurisdictions glossary entry; timely filing glossary entry; Medicare behavioral health billing guide.
FAQs
Who administers Medicare Part B in Illinois?
CMS lists National Government Services, Inc. as the Jurisdiction 6 MAC for Illinois, Minnesota and Wisconsin. Confirm the current contractor before you submit anything.
How long do I have to file a Medicare claim?
Generally 12 months, or one calendar year, from the date of service. Limited exceptions exist in the CMS manual.
Can an LCSW or MFT bill Medicare?
Yes. CMS lists clinical social workers, marriage and family therapists and mental health counselors, and they must accept assignment.
Is Medicare telehealth for therapy still covered?
CMS says mental health telehealth is covered permanently, with the in-person requirement waived through December 31, 2027.
