DR. RON S GEJMAN MD, PHD
NPI 1811523848
Internal Medicine - Medical Oncology in New York, NY
About Dr. Ron S Gejman Md, Phd NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. RON S GEJMAN MD, PHD (NPI 1811523848) is an individual medical oncology provider in New York, New York, licensed in New York (323560) and active in the NPI registry since March 2020. He is enrolled in Medicare PECOS, is affiliated with New York-presbyterian Hospital, and is a graduate of Other (2020).
NPPES Registry Identity
Specialties & Licenses 2
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. Ron S Gejman Md, Phd 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 Reassignment
Medicare enrollment records show Ron Gejman reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
New York, NY 10032
- Reassigned Medicare billing, New York enrollment
- 3,922 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.
New York-Presbyterian Hospital
Acute Care Hospitals · New York, NYPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 10032 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 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
NEW YORK, NY 10032
NEW YORK, NY 10032
NEW YORK, NY 10032
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 Ron Gejman's NPI number?
The NPI number for Ron Gejman is 1811523848. It was assigned to this individual provider in the NPPES registry on March 21, 2020.
Where is Ron Gejman located?
Ron Gejman practices at 177 Fort Washington Ave Mhb 6gn-435, New York, NY 10032. The listed phone number is (212) 305-8923.
What is Ron Gejman's specialty?
The primary specialty registered for this NPI is Internal Medicine, specializing in Medical Oncology, with taxonomy code 207RX0202X.
Is Ron Gejman enrolled in Medicare?
Yes. Ron Gejman 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 organization bills Medicare for Ron Gejman's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Ron Gejman reassigns Medicare benefits to Trustees Of Columbia University In The City Of New York (New York, NY). The 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 Ron Gejman's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
Is Ron Gejman affiliated with any hospitals?
According to CMS data, Ron Gejman is affiliated with New York-Presbyterian Hospital.
When was this NPI record last updated?
The NPPES record for Ron Gejman was last updated on April 30, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 6 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. Ron S Gejman, MD, PHD · NPI 1811523848
Medical Oncology physician in New York, New York. Individual provider, active in the CMS NPPES registry since March 21, 2020.
## Identity
- **NPI:** 1811523848 (Entity type: Individual)
- **Enumerated:** March 21, 2020
- **Primary specialty:** Internal Medicine - Medical Oncology · taxonomy 207RX0202X
- **State license:** 323560 (New York)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 177 FORT WASHINGTON AVE, MHB 6GN-435, New York, NY 10032-3733
- **Phone:** (212) 305-8923
## 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:** Trustees Of Columbia University In The City Of New York (NPI 1508266347, New York, NY), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2020
## Record status
- **NPPES last updated:** April 30, 2026
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Source: [NPI Profile](https://npiprofile.com/npi/1811523848) · Data from the CMS NPPES public registry.