DR. OTHON ILIOPOULOS MD
NPI 1447352448
Internal Medicine - Medical Oncology in Boston, MA
About Dr. Othon Iliopoulos Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
DR. OTHON ILIOPOULOS MD (NPI 1447352448) is an individual medical oncology provider in Boston, Massachusetts, licensed in Massachusetts (76267) and active in the NPI registry since September 2006. He is enrolled in Medicare PECOS, is affiliated with Massachusetts General Hospital, and is a graduate of Other (1985).
NPPES Registry Identity
Specialties & Licenses
Other Identifiers 5
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. Othon Iliopoulos 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 Othon Iliopoulos reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Boston, MA 02114
- Reassigned Medicare billing, Massachusetts enrollment
- 6,360 clinicians in this Medicare group
Boston, MA 02114
- Reassigned Medicare billing, Massachusetts enrollment
- 6,234 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 2
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 2
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Massachusetts General Hospital
Acute Care Hospitals · Boston, MABrigham And Women's Hospital
Acute Care Hospitals · Boston, MAPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 02114 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 4
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 11
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
BOSTON, MA 02114
BOSTON, MA 02114
BOSTON, MA 02114
BOSTON, MA 02114
BOSTON, MA 02114
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 Othon Iliopoulos's NPI number?
The NPI number for Othon Iliopoulos is 1447352448. It was assigned to this individual provider in the NPPES registry on September 1, 2006.
Where is Othon Iliopoulos located?
Othon Iliopoulos practices at 100 Blossom Street Yaw 7 Massachusetts General Hospital, Boston, MA 02114. The listed phone number is (617) 724-3404.
What is Othon Iliopoulos's specialty?
The primary specialty registered for this NPI is Internal Medicine, specializing in Medical Oncology, with taxonomy code 207RX0202X.
Is Othon Iliopoulos enrolled in Medicare?
Yes. Othon Iliopoulos 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 Othon Iliopoulos's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Othon Iliopoulos reassigns Medicare benefits to 2 organizations: Massachusetts General Physicians Organization Inc (Boston, MA) and The General Hospital Corporation (Boston, MA). 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 Othon Iliopoulos's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
Is Othon Iliopoulos affiliated with any hospitals?
According to CMS data, Othon Iliopoulos is affiliated with Massachusetts General Hospital and Brigham And Women's Hospital.
When was this NPI record last updated?
The NPPES record for Othon Iliopoulos was last updated on December 18, 2012. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 13 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.
# Dr. Othon Iliopoulos, MD · NPI 1447352448
Medical Oncology physician in Boston, Massachusetts. Individual provider, active in the CMS NPPES registry since September 1, 2006.
## Identity
- **NPI:** 1447352448 (Entity type: Individual)
- **Enumerated:** September 1, 2006
- **Primary specialty:** Internal Medicine - Medical Oncology · taxonomy 207RX0202X
- **State license:** 76267 (Massachusetts)
- **Sole proprietor:** No
## Practice location
- **Address:** 100 BLOSSOM STREET, YAW 7 MASSACHUSETTS GENERAL HOSPITAL, Boston, MA 02114-2617
- **Phone:** (617) 724-3404 · **Fax:** (617) 726-8623
## 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): Massachusetts General Physicians Organization Inc (NPI 1801874573, Boston, MA); The General Hospital Corporation (NPI 1023049236, Boston, MA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 1985
## Record status
- **NPPES last updated:** December 18, 2012
- **Other identifiers:** Other J12656 (MA); Other 076267 (MA); Medicare UPIN F30190; and 2 more
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Source: [NPI Profile](https://npiprofile.com/npi/1447352448) · Data from the CMS NPPES public registry.