Dianna Mung-Fung Mak, DO
Family Medicine Physician · Rancho Cucamonga, CA
Dianna Mung-Fung Mak, DO is a family medicine physician with a practice address in Rancho Cucamonga, California, and NPI 1104936988, issued on Aug 30, 2006. Check the license (California 20A5237, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Dianna Mung-Fung Mak
- Credential
- DO
- Primary taxonomy
- Family Medicine Physician 207Q00000X
- License number
- 20A5237 CA
Self-reported in NPPES; status is on the state search - Practice location
- 9089 Baseline Road, Rancho Cucamonga, CA 91730
- Phone
- (909) 483-0505
- Enumerated
- Aug 30, 2006
- Record last updated
- Jan 11, 2024
- Fax
- (909) 483-0508
- Medicaid ID
- 00AX52370 CA
- Medicare enrollment
- Enrolled (PECOS I20111013000560); accepts Medicare assignment
- Medical or professional school
- Michigan State University College Of Osteopathic Medicine, 1981
- Entity
- Type 1 · individual
8 nearest family medicine physician records → All 17,133 in California → Look up another NPI →
Verify Dianna Mung-Fung Mak in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A5237Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
96% fewer Medicare Part D claims than the average family medicine physician in 2024
136 Medicare Part D claims for 38 beneficiaries, against an average of 3,544 among the 117,163 providers of this specialty who prescribed in Part D. Brand-name drugs were 9% of claims.
Most prescribed
- Levothyroxine Sodium15 claims
- Rosuvastatin Calcium12 claims
- Atorvastatin Calcium11 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 one group practice
- Inland Physicians Service IncRancho Cucamonga, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Dianna Mung-Fung Mak among 17,133 family medicine physician records in California
Dianna Mung-Fung Mak, DO is one of 17,133 family medicine physician records with a practice address in California. 81% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 6% of them.
- NPI issued2006 · 6% of these records are older, 59% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileYes · 62% of these records are
- Graduated1981 · median 2005 among the 10,652 with a school on file
- Record last updated2024 · 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 California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
62 family medicine physician records list a practice address in Rancho Cucamonga
They are 62 of the 4,579 NPPES records with a practice address in Rancho Cucamonga, and 17,133 family medicine physician records in California.
All 17,133 in California → Every provider in Rancho Cucamonga → Family Medicine Physician nationwide →
The 8 family medicine physician records with the nearest ZIP codes
- Marc Avent, DORancho Cucamonga, CA 917301437104783
- Eldine Banquerigo, M.D.Rancho Cucamonga, CA 917301851367528
- Steven Barag, D.O.Rancho Cucamonga, CA 917301366444838
- James Brown, M.D.Rancho Cucamonga, CA 917301073597738
- Juan Cortes, DORancho Cucamonga, CA 917301760432181
- Rommie Fakhoury, MDRancho Cucamonga, CA 917301528000643
- Sandra Force-Obrowski, M.D.Rancho Cucamonga, CA 917301023034873
- Patricia Guevara-Channell, MDRancho Cucomonga, CA 917301841266392
Common questions
What is Dianna Mung-Fung Mak, DO's NPI number?
Dianna Mung-Fung Mak, DO's National Provider Identifier (NPI) is 1104936988, issued on Aug 30, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Dianna Mung-Fung Mak, DO located?
The NPPES record lists a practice address at 9089 Baseline Road, Rancho Cucamonga, CA, 91730. Phone: (909) 483-0505. Providers update this record themselves, so call before visiting.
How can I verify Dianna Mung-Fung Mak, DO's license?
NPPES lists California license number 20A5237, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Dianna Mung-Fung Mak, DO prescribe under Medicare Part D?
In 2024, Dianna Mung-Fung Mak, DO had 136 Medicare Part D claims for 38 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.