MARK JIARAS LTD
NPI 1336502434
Community/Behavioral Health in Chicago, IL
About Mark Jiaras Ltd NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MARK JIARAS LTD (NPI 1336502434) is a healthcare organization registered as a community/behavioral health in Chicago, Illinois and active in the NPI registry since April 2016. The organization lists Mark Jiaras, President, as its authorized official.
NPPES Registry Identity
Specialties & Licenses
Medicare Participation & PECOS CMS
Medicare enrollment and the clinicians who bill Medicare through this organization, from CMS.
Medicare Enrollment Status
Enrolled in Medicare (PECOS)
Mark Jiaras Ltd is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).
Clinicians Billing Medicare Through This Organization
Medicare enrollment records show 1 clinician reassigns Medicare billing to Mark Jiaras Ltd, which bills Medicare for the services this clinician delivers.
Clinician (1)
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
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 Jiaras Ltd's NPI number?
The NPI number for Mark Jiaras Ltd is 1336502434. It was assigned to this organization in the NPPES registry on April 5, 2016.
Where is Mark Jiaras Ltd located?
Mark Jiaras Ltd is located at 4200 W Peterson Ave Suite 105, Chicago, IL 60646. The listed phone number is (847) 630-3900.
What is Mark Jiaras Ltd's specialty?
The primary specialty registered for this NPI is Community/Behavioral Health with taxonomy code 251S00000X.
Is Mark Jiaras Ltd enrolled in Medicare?
Yes. Mark Jiaras Ltd is registered in the Medicare PECOS enrollment system.
How many clinicians bill Medicare through Mark Jiaras Ltd?
According to the CMS Revalidation Reassignment List (October 2026 release), 1 clinician (Clinical Psychologist) reassigns their Medicare billing to Mark Jiaras Ltd. A 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 the clinician's services. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
When was this NPI record last updated?
The NPPES record for Mark Jiaras Ltd was last updated on April 5, 2016. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 years 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.
# Mark Jiaras Ltd · NPI 1336502434
Community/Behavioral Health organization in Chicago, Illinois. Organization record, active in the CMS NPPES registry since April 5, 2016.
## Identity
- **NPI:** 1336502434 (Entity type: Organization)
- **Enumerated:** April 5, 2016
- **Primary specialty:** Community/Behavioral Health · taxonomy 251S00000X
- **Organization subpart:** No
- **Authorized official:** Mark Jiaras, PRESIDENT
## Practice location
- **Address:** 4200 W PETERSON AVE, SUITE 105, Chicago, IL 60646-6074
- **Phone:** (847) 630-3900
## Medicare
- **Medicare:** Enrolled in Medicare (PECOS)
- **Clinicians billing through this organization:** 1 clinician (Clinical Psychologist) reassigns Medicare billing to this organization (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
## Record status
- **NPPES last updated:** April 5, 2016
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Source: [NPI Profile](https://npiprofile.com/npi/1336502434) · Data from the CMS NPPES public registry.