Gary L. Horowitz, M.D.
Chemical Pathology Physician · Boston, MA
Gary L. Horowitz, M.D. is a chemical pathology physician with a practice address in Boston, Massachusetts, and NPI 1558308213, issued on Jun 1, 2006. Check the license (Massachusetts 44883, as entered in NPPES) on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.
- Name
- Gary L. Horowitz
- Credential
- M.D.
- Primary taxonomy
- Chemical Pathology Physician 207ZP0104X
- License number
- 44883 MA
Self-reported in NPPES; status is on the state search - Practice location
- Beth Israel Hospital, Boston, MA 02215
- Phone
- (617) 667-3648
- Enumerated
- Jun 1, 2006
- Record last updated
- Jul 13, 2026
- Medicare enrollment
- Enrolled (PECOS I20050406000555); accepts Medicare assignment
- Medical or professional school
- Harvard Medical School, 1976
- Entity
- Type 1 · individual
1 nearest chemical pathology physician record → All 2 in Massachusetts → Look up another NPI →
Also registered at Beth Israel Hospital
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Steven Freedman, M.D.Gastroenterology Physician1952335796
- Olivier Nicolas Kocher, M.D.Anatomic Pathology Physician1669586566
- Nadine Muskatel Tung, M.D.Hematology & Oncology Physician1609800366
Verify Gary L. Horowitz in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMassachusetts Board of Registration in Medicine
Search for license 44883Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Bills Medicare through one group practice
- Pratt Pathology Associates IncBoston, MA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Chemical Pathology Physician providers in Massachusetts
There are 2 chemical pathology physician records in Massachusetts.
All 2 in Massachusetts → Every provider in Boston → Chemical Pathology Physician nationwide →
The 1 chemical pathology physician record with the nearest ZIP codes
- David KembleBoston, MA 022151396503041
Common questions
What is Gary L. Horowitz, M.D.'s NPI number?
Gary L. Horowitz, M.D.'s National Provider Identifier (NPI) is 1558308213, issued on Jun 1, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Gary L. Horowitz, M.D. located?
The NPPES record lists a practice address at Beth Israel Hospital, Boston, MA, 02215. Phone: (617) 667-3648. Providers update this record themselves, so call before visiting.
How can I verify Gary L. Horowitz, M.D.'s license?
NPPES lists Massachusetts license number 44883, as entered by the provider. Search the Massachusetts Board of Registration in Medicine at https://findmydoctor.mass.gov/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.