Mary K. Diehn, M.D.
Family Medicine Physician · Baltimore, MD
Mary K. Diehn, M.D. is a family medicine physician with a practice address in Baltimore, Maryland, and NPI 1780029777, issued on May 3, 2013. Check the license (Maryland D0082274, as entered in NPPES) on the Maryland Board of Physicians; the Medicare figures below come from public CMS files.
- Name
- Mary K. Diehn
- Credential
- M.D.
- Primary taxonomy
- Family Medicine Physician 207Q00000X
- License number
- D0082274 MD
Self-reported in NPPES; status is on the state search - Practice location
- 9000 Franklin Square Dr, Baltimore, MD 21237
- Phone
- (443) 777-2000
- Enumerated
- May 3, 2013
- Record last updated
- Sep 6, 2022
- Entity
- Type 1 · individual
8 nearest family medicine physician records → All 1,912 in Maryland → Look up another NPI →
Also registered at 9000 Franklin Square Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Mary K. Diehn in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMaryland Board of Physicians
Search for license D0082274Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
43% fewer Medicare Part D claims than the average family medicine physician in 2024
2,003 Medicare Part D claims for 51 beneficiaries, against an average of 3,544 among the 117,163 providers of this specialty who prescribed in Part D. Brand-name drugs were 18% of claims. 64 claims were for opioids.
Most prescribed
- Atorvastatin Calcium184 claims
- Amlodipine Besylate86 claims
- Gabapentin86 claims
- Lisinopril81 claims
- Losartan Potassium77 claims
- Albuterol Sulfate Hfa69 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.
Industry payments in 2024: $121.19
2 payments; by number, the most common kind was food and beverage; the largest payer was Abbvie Inc. The 55,478 providers of this specialty with any payment received $902.55 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Mary K. Diehn among 1,912 family medicine physician records in Maryland
Mary K. Diehn, M.D. is one of 1,912 family medicine physician records with a practice address in Maryland. 73% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2013, is newer than 72% of them.
- NPI issued2013 · 72% of these records are older, 25% newer
- In a Medicare fileYes · 73% of these records are
- In the CMS Doctors and Clinicians fileNo · 60% of these records are
- 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 Maryland practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Family Medicine Physician providers in Maryland
There are 1,912 family medicine physician records in Maryland.
All 1,912 in Maryland → Every provider in Baltimore → Family Medicine Physician nationwide →
The 8 family medicine physician records with the nearest ZIP codes
- Nancy Barr, M.D.Rosedale, MD 212371881636595
- Florence Deza, M.D.Baltimore, MD 212371659340560
- Michael Dwyer, M.D.Baltimore, MD 212371457320939
- Maryellen Goodell, MDBaltimore, MD 212371841244167
- Yoon Kim, MDBaltimore, MD 212371003893116
- Joyce KingBaltimore, MD 212371851360440
- Jamshid Mian, MDBaltimore, MD 212371538143953
- John NiehoffBaltimore, MD 212371447229349
Common questions
What is Mary K. Diehn, M.D.'s NPI number?
Mary K. Diehn, M.D.'s National Provider Identifier (NPI) is 1780029777, issued on May 3, 2013. An NPI identifies a provider in billing; it is not a license.
Where is Mary K. Diehn, M.D. located?
The NPPES record lists a practice address at 9000 Franklin Square Dr, Baltimore, MD, 21237. Phone: (443) 777-2000. Providers update this record themselves, so call before visiting.
How can I verify Mary K. Diehn, M.D.'s license?
NPPES lists Maryland license number D0082274, as entered by the provider. Search the Maryland Board of Physicians at https://www.mbp.state.md.us/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Mary K. Diehn, M.D. prescribe under Medicare Part D?
In 2024, Mary K. Diehn, M.D. had 2,003 Medicare Part D claims for 51 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.