MARK MORRIS HAMMER M.D.
NPI 1578884003
Radiology - Diagnostic Radiology in Boston, MA
About Mark Morris Hammer M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MARK MORRIS HAMMER M.D. (NPI 1578884003) is an individual diagnostic radiology provider in Boston, Massachusetts, licensed in Massachusetts (265846) and active in the NPI registry since June 2010. He is enrolled in Medicare PECOS, is affiliated with Massachusetts General Hospital, and maintains a secondary practice location in Boston.
NPPES Registry Identity
Specialties & Licenses
Secondary Practice Location 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
Mark Morris Hammer M.d. 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 Hammer reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Boston, MA 02115
- Reassigned Medicare billing, Massachusetts enrollment
- 4,574 clinicians in this Medicare group
South Weymouth, MA 02190
- Reassigned Medicare billing, Massachusetts enrollment
- 419 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 13
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 4
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Massachusetts General Hospital
Acute Care Hospitals · Boston, MANewton-Wellesley Hospital
Acute Care Hospitals · Newton, MABrigham And Women's Hospital
Acute Care Hospitals · Boston, MAFaulkner Hospital-Brigham And Women's
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.
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.
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 Mark Hammer's NPI number?
The NPI number for Mark Hammer is 1578884003. It was assigned to this individual provider in the NPPES registry on June 18, 2010.
Where is Mark Hammer located?
Mark Hammer practices at 55 Fruit St, Boston, MA 02114. The listed phone number is (617) 726-2000.
What is Mark Hammer's specialty?
The primary specialty registered for this NPI is Radiology, specializing in Diagnostic Radiology, with taxonomy code 2085R0202X.
Is Mark Hammer enrolled in Medicare?
Yes. Mark Hammer 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 Hammer's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Mark Hammer reassigns Medicare benefits to 2 organizations: Brigham & Womens Physicians Organization Inc (Boston, MA) and Harbor Medical Associates, Inc. (South Weymouth, 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 Mark Hammer's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Mark Hammer accept?
Health plans from Taro Health list Mark Hammer 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 Hammer affiliated with any hospitals?
According to CMS data, Mark Hammer is affiliated with Massachusetts General Hospital, Newton-Wellesley Hospital, Brigham And Women's Hospital and Faulkner Hospital-Brigham And Women's.
When was this NPI record last updated?
The NPPES record for Mark Hammer was last updated on August 21, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 2 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.
# Mark Morris Hammer, M.D. · NPI 1578884003
Diagnostic Radiology physician in Boston, Massachusetts. Individual provider, active in the CMS NPPES registry since June 18, 2010.
## Identity
- **NPI:** 1578884003 (Entity type: Individual)
- **Enumerated:** June 18, 2010
- **Primary specialty:** Radiology - Diagnostic Radiology · taxonomy 2085R0202X
- **State license:** 265846 (Massachusetts)
- **Sole proprietor:** No
## Practice location
- **Address:** 55 FRUIT ST, Boston, MA 02114-2621
- **Phone:** (617) 726-2000
## 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): Brigham & Womens Physicians Organization Inc (NPI 1033535497, Boston, MA); Harbor Medical Associates, Inc. (NPI 1124079561, South Weymouth, MA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Stanford University School Of Medicine, class of 2010
## Record status
- **NPPES last updated:** August 21, 2026
---
Source: [NPI Profile](https://npiprofile.com/npi/1578884003) · Data from the CMS NPPES public registry.