Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
NPIDirectory

Dr. Mark Steven Pasternack, MD

Individual provider Internal Medicine Physician · NPI 1861458101

Dr. Mark Steven Pasternack, MD is registered under Infectious Disease in Boston, Massachusetts. Graduated from Harvard Medical School in 1975, 51 years ago. Practices with Massachusetts General Physicians Organization Inc, a 3,484-clinician group and accepts Medicare assignment. Licensed in Massachusetts.

Years since qualifying
51
Trained at
Harvard Medical School
Licensed in
MA
In the registry since
2006
Specialties on file
2
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

15 Parkman St Wac 612
Boston, MA 02114-3117 Not confirmed with CMS for 14 years — call before visiting
Phone: (617) 726-5771
Fax: (617) 726-5411
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Internal Medicine Physician (primary) Taxonomy 207R00000X · Licence 42794 (MA)
Infectious Disease Physician Taxonomy 207RI0200X · Licence 42794 (MA)

Record details

NPI number1861458101
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedApril 25, 2006
Last updated in NPPESOctober 4, 2011

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyINFECTIOUS DISEASE
Also practisesINTERNAL MEDICINE
Medical schoolHARVARD MEDICAL SCHOOL
Graduated 1975 (51 years in practice)
Group practice Massachusetts General Physicians Organization Inc — 3484 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations3 on file with Medicare

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients103
Services billed 239 a service is one billed item, such as a visit, a test or a procedure
Average patient age74

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician. Those with a page here are linked.

Also affiliated with 1 inpatient rehabilitation facility, which CMS identifies by certification number only.

Colleagues at Massachusetts General Physicians Organization Inc

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 3484 clinicians in the practice; 12 are shown here.

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