GHASSAN ZALZALEH MD
NPI 1992704035
Internal Medicine - Hematology & Oncology in Oak Lawn, IL
About Ghassan Zalzaleh Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
GHASSAN ZALZALEH MD (NPI 1992704035) is an individual hematology & oncology provider in Oak Lawn, Illinois, licensed in Illinois (036089713) and active in the NPI registry since July 2005. He is enrolled in Medicare PECOS, is affiliated with Advocate Trinity Hospital, and is a graduate of Other (1987).
NPPES Registry Identity
Specialties & Licenses
Other Identifiers 2
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
Ghassan Zalzaleh 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
3Medicare enrollment records show Ghassan Zalzaleh reassigns Medicare billing to 3 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Oak Lawn, IL 60453
- Reassigned Medicare billing, Illinois enrollment
- 57 clinicians in this Medicare group
Oak Lawn, IL 60453
- Reassigned Medicare billing, Illinois enrollment
- Medicare enrollment name: Advocate Health And Hospitals Corporation
- 4,870 clinicians in this Medicare group
Hinsdale, IL 60521
- Reassigned Medicare billing, Illinois enrollment
- 44 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.
Areas of Expertise CMS Part B claims 56
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Hospital Affiliations CMS Care Compare 5
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Advocate Trinity Hospital
Acute Care Hospitals · Chicago, ILPalos Community Hospital
Acute Care Hospitals · Palos Heights, ILAdvocate Christ Hospital & Medical Center
Acute Care Hospitals · Oak Lawn, ILSilver Cross Hospital And Medical Centers
Acute Care Hospitals · New Lenox, ILNorthwestern Medicine Central Dupage Hospital
Acute Care Hospitals · Winfield, ILPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 60453 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Referred Medical Equipment & Supplies CMS DME claims 3
Durable medical equipment, devices and supplies this provider ordered from DME suppliers for patients, from Medicare fee-for-service claims.
Other Providers at the Same Location NPPES 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
OAK LAWN, IL 60453
OAK LAWN, IL 60453
OAK LAWN, IL 60453
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 Ghassan Zalzaleh's NPI number?
The NPI number for Ghassan Zalzaleh is 1992704035. It was assigned to this individual provider in the NPPES registry on July 20, 2005.
Where is Ghassan Zalzaleh located?
Ghassan Zalzaleh practices at 4400 W 95th St Suite 311, Oak Lawn, IL 60453. The listed phone number is (708) 424-9710.
What is Ghassan Zalzaleh's specialty?
The primary specialty registered for this NPI is Internal Medicine, specializing in Hematology & Oncology, with taxonomy code 207RH0003X.
Is Ghassan Zalzaleh enrolled in Medicare?
Yes. Ghassan Zalzaleh 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 Ghassan Zalzaleh's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Ghassan Zalzaleh reassigns Medicare benefits to 3 organizations: Affiliated Oncologists, LLC (Oak Lawn, IL), Advocate Health & Hospitals Corporation (Oak Lawn, IL) and Ahp Specialty Care Nfp (Hinsdale, IL). 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 Ghassan Zalzaleh's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Ghassan Zalzaleh accept?
Health plans from Ambetter Health, Ambetter Health of Delaware and Ambetter from Home State Health list Ghassan Zalzaleh 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 Ghassan Zalzaleh affiliated with any hospitals?
According to CMS data, Ghassan Zalzaleh is affiliated with Advocate Trinity Hospital, Palos Community Hospital, Advocate Christ Hospital & Medical Center, Silver Cross Hospital And Medical Centers and Northwestern Medicine Central Dupage Hospital.
When was this NPI record last updated?
The NPPES record for Ghassan Zalzaleh was last updated on July 10, 2015. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 11 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.