DR. MARK D WILLIAMS MD
NPI 1659461564
Internal Medicine - Pulmonary Disease in Indianapolis, IN
About Dr. Mark D Williams Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. MARK D WILLIAMS MD (NPI 1659461564) is an individual pulmonary disease provider in Indianapolis, Indiana, licensed in Indiana (01041431A) and active in the NPI registry since October 2006. He is enrolled in Medicare PECOS, is affiliated with Indiana University Health, and maintains a secondary practice location in Indianapolis.
NPPES Registry Identity
Specialties & Licenses
Secondary Practice Location 1
Other Identifiers 1
Accepted Insurance
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Dr. Mark D Williams Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignments
2Medicare enrollment records show Mark Williams reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Indianapolis, IN 46202
- Reassigned Medicare billing, Indiana enrollment
- 318 clinicians in this Medicare group
Indianapolis, IN 46202
- Reassigned Medicare billing, Indiana enrollment
- 5,212 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Hospital Affiliations CMS Care Compare
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Indiana University Health
Acute Care Hospitals · Indianapolis, INPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 46202 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Other Providers at the Same Location NPPES 11
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
INDIANAPOLIS, IN 46202
INDIANAPOLIS, IN 46202
INDIANAPOLIS, IN 46202
INDIANAPOLIS, IN 46202
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is Mark Williams's NPI number?
The NPI number for Mark Williams is 1659461564. It was assigned to this individual provider in the NPPES registry on October 13, 2006.
Where is Mark Williams located?
Mark Williams practices at 1801 N Senate Ave Suite 230, Indianapolis, IN 46202. The listed phone number is (317) 962-5820.
What is Mark Williams's specialty?
The primary specialty registered for this NPI is Internal Medicine, specializing in Pulmonary Disease, with taxonomy code 207RP1001X.
Is Mark Williams enrolled in Medicare?
Yes. Mark Williams is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organizations bill Medicare for Mark Williams's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Mark Williams reassigns Medicare benefits to 2 organizations: Indiana Clinic Critical Care LLC (Indianapolis, IN) and Iu Health Medical Group, LLC (Indianapolis, IN). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Mark Williams's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Mark Williams accept?
Health plans from Ambetter Health, Ambetter from Buckeye Health Plan, Ambetter from Meridian, Anthem Blue Cross and Blue Shield and CareSource and 2 other insurers list Mark Williams as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
Is Mark Williams affiliated with any hospitals?
According to CMS data, Mark Williams is affiliated with Indiana University Health.
When was this NPI record last updated?
The NPPES record for Mark Williams was last updated on March 15, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 19 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Dr. Mark D Williams, MD · NPI 1659461564
Pulmonary Disease physician in Indianapolis, Indiana. Individual provider, active in the CMS NPPES registry since October 13, 2006.
## Identity
- **NPI:** 1659461564 (Entity type: Individual)
- **Enumerated:** October 13, 2006
- **Primary specialty:** Internal Medicine - Pulmonary Disease · taxonomy 207RP1001X
- **State license:** 01041431A (Indiana)
- **Sole proprietor:** No
## Practice location
- **Address:** 1801 N SENATE AVE, SUITE 230, Indianapolis, IN 46202-1252
- **Phone:** (317) 962-5820 · **Fax:** (317) 962-3916
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 2 organizations under Medicare reassignment (form CMS-855R): Indiana Clinic Critical Care LLC (NPI 1417285230, Indianapolis, IN); Iu Health Medical Group, LLC (NPI 1326893777, Indianapolis, IN) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Indiana University School Of Medicine, class of 1990
## Record status
- **NPPES last updated:** March 15, 2025
- **Other identifiers:** Medicaid 200104270 (IN)
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Source: [NPI Profile](https://npiprofile.com/npi/1659461564) · Data from the CMS NPPES public registry.