Zachary John Kosak, MD
Family Medicine Physician · Philadelphia, PA
Zachary John Kosak, MD is a family medicine physician with a practice address in Philadelphia, Pennsylvania, and NPI 1619438322, issued on Mar 26, 2019. Check the license (Pennsylvania MD476679, as entered in NPPES) on the Pennsylvania Department of State (PALS); the Medicare figures below come from public CMS files.
- Name
- Zachary John Kosak
- Credential
- MD
- Primary taxonomy
- Family Medicine Physician 207Q00000X
- License number
- MD476679 PA
Self-reported in NPPES; status is on the state search - Practice location
- 3737 Market St FL 9, Philadelphia, PA 19104
- Phone
- (215) 662-8777
- Enumerated
- Mar 26, 2019
- Record last updated
- Oct 25, 2022
- Fax
- (215) 243-4601
- Medicare enrollment
- Enrolled (PECOS I20220913000033); accepts Medicare assignment
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest family medicine physician records → All 7,483 in Pennsylvania → Look up another NPI →
Also registered at 3737 Market St FL 9
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Zachary John Kosak in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersPennsylvania Department of State (PALS)
Search for license MD476679Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
60% fewer Medicare Part D claims than the average family medicine physician in 2024
1,424 Medicare Part D claims for 176 beneficiaries, against an average of 3,544 among the 117,163 providers of this specialty who prescribed in Part D. Brand-name drugs were 16% of claims. 48 claims were for opioids.
Most prescribed
- Atorvastatin Calcium84 claims
- Albuterol Sulfate Hfa78 claims
- Omeprazole51 claims
- Ozempic50 claims
- Gabapentin46 claims
- Amlodipine Besylate43 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Bills Medicare through 2 group practices
- Trustees OF The University OF PennsylvaniaPhiladelphia, PA
- University OF Penn - Medical GroupPhiladelphia, PA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Zachary John Kosak among 7,483 family medicine physician records in Pennsylvania
Zachary John Kosak, MD is one of 7,483 family medicine physician records with a practice address in Pennsylvania. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2019, is newer than 81% of them.
- NPI issued2019 · 81% of these records are older, 17% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 61% of these records are
- Graduated2019 · median 2005 among the 4,529 with a school on file
- Record last updated2022 · 58% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207Q00000X and a Pennsylvania practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
800 family medicine physician records list a practice address in Philadelphia
They are 800 of the 42,849 NPPES records with a practice address in Philadelphia, and 7,483 family medicine physician records in Pennsylvania.
All 7,483 in Pennsylvania → Every provider in Philadelphia → Family Medicine Physician nationwide →
The 8 family medicine physician records with the nearest ZIP codes
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Common questions
What is Zachary John Kosak, MD's NPI number?
Zachary John Kosak, MD's National Provider Identifier (NPI) is 1619438322, issued on Mar 26, 2019. An NPI identifies a provider in billing; it is not a license.
Where is Zachary John Kosak, MD located?
The NPPES record lists a practice address at 3737 Market St FL 9, Philadelphia, PA, 19104. Phone: (215) 662-8777. Providers update this record themselves, so call before visiting.
How can I verify Zachary John Kosak, MD's license?
NPPES lists Pennsylvania license number MD476679, as entered by the provider. Search the Pennsylvania Department of State (PALS) at https://www.pals.pa.gov/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Zachary John Kosak, MD prescribe under Medicare Part D?
In 2024, Zachary John Kosak, MD had 1,424 Medicare Part D claims for 176 beneficiaries; the average among family medicine physician prescribers was 3,544. Part D covers Medicare prescriptions only.
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.