Dr. James Matthew Diffley, MD
- Hospital affiliations
- 2
- Medical group
- 1
- Insurance carriers
- 1
- State license
- 1
- Year NPI issued
- 2011
- Practice address
- 1425 S Main Street, Walnut Creek, CA 94596
- Practice phone
- Call (925) 295-4000
- Professional email
- Get professional email
- Personal email
- Get personal email
- Mobile number
- Get mobile number
Primary practice
Find Dr. Diffley's professional email, personal email and mobile number
Dmand AI checks each channel through healthcare-specific waterfall enrichment. See what is on file with a free account, with practice phones, licenses and affiliations.
Dr. James Matthew Diffley is a pediatrician in Walnut Creek, California
Dr. Diffley practices at Walnut Creek Medical Center in Walnut Creek, California, part of Kaiser Permanente.
Dr. Diffley's NPI, 1780974626, was assigned on April 12, 2011. Dr. Diffley graduated from OU College of Medicine in 2009. Dr. Diffley holds California license A114288.
- NPI
- 1780974626NPI Registry (opens in a new tab)
- NPI enumeration date
- April 12, 2011
- NPI status
- Active
- Practice phone
- (925) 295-4000
- Professional email
- Get email
- Personal email
- Get email
- Mobile number
- Get number
- Sex
- Male
- Medical school graduation
- 2009
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Affiliation Data
Dr. James Matthew Diffley practices at Walnut Creek Medical Center in Walnut Creek, California
Dr. Diffley's primary practice is Walnut Creek Medical Center, at 1425 S Main Street, Walnut Creek, CA 94596 in Contra Costa County. The practice phone is (925) 295-4000.
- Walnut Creek Medical Center1425 S Main Street, Walnut Creek, CA 94596 · Contra Costa CountyPhone(925) 295-4000
Source: Dmand AI Affiliation Data
Dr. James Matthew Diffley is affiliated with 2 sites of care and 1 medical group
Dr. Diffley's primary practice is Walnut Creek Medical Center in Walnut Creek, California, part of Kaiser Permanente. Dr. Diffley is also affiliated with UCSF Benioff Children's Hospital Oakland. The medical group on file is The Permanente Medical Group, Inc.
Sources: Dmand AI Affiliation Data; and Dmand AI Org Hierarchy Data
Dmand AI tracks the EHR system at Dr. James Matthew Diffley's practice
Dmand AI tracks the electronic health record (EHR) system at each site where Dr. Diffley practices, 2 sites in all. Vendor and product names are available with a free account.
| Site | EHR vendor and product |
|---|---|
| Walnut Creek Medical Center | Available with a free account |
| +1 more affiliated site | Available with a free account |
Source: Dmand AI Technology Install Data
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Dr. James Matthew Diffley is one of 8,236 pediatricians in California
Pediatrics is Dr. Diffley's primary specialty in the NPI Registry, under taxonomy code 208000000X. Dr. Diffley is board certified in pediatric hospital medicine by the American Board of Pediatrics. Dr. Diffley is licensed in California.
Specialties and state licenses
- Pediatrics, CaliforniaPrimary
Pediatricians near Dr. Diffley
Counts of pediatricians with a Dmand AI profile, by place and practice. Each opens the list.
Sources: NPPES NPI Registry (CMS); Dmand AI Professional Profile Data; and Dmand AI Peer Benchmarks
Dr. James Matthew Diffley's patients have a median age of 8
Across all payers, Dmand AI patient panel data puts Dr. Diffley's median patient age at 8, with 70% women.
Dr. Diffley's patients across all payers
Dmand AI patient panel data covers Medicare, Medicaid and commercial patients.
Patient panel by age, all payers
Median age 8
Patient panel by sex, all payers
- Women70%
- Men30%
Source: Dmand AI Patient Panel Data
Dr. James Matthew Diffley graduated from OU College of Medicine
Dr. Diffley graduated from OU College of Medicine in 2009.
- Medical school
- Board certified in pediatric hospital medicine
- Board certified in pediatrics
Source: Dmand AI Professional Profile Data
Dr. James Matthew Diffley accepts plans from 1 insurance carrier
Dr. Diffley is in network with 1 carrier, including Kaiser Permanente. EPO plans come from the most carriers, 1. Check the plan with the practice before a visit.
- Kaiser Permanente
Plan types Dr. Diffley accepts, by number of carriers
- EPO1
- HMO1
- POS1
Source: Dmand AI Insurance Network Data
Sources for Dr. James Matthew Diffley's profile data
| Data on this page | Source |
|---|---|
| NPI, name, sex, specialty and licenses | NPPES NPI Registry (CMS) (opens in a new tab)Dmand AI Professional Profile Data |
| Practice locations and phone | Dmand AI Affiliation Data |
| Primary practice, affiliations and health system | Dmand AI Affiliation DataDmand AI Org Hierarchy Data |
| Medicare patients and the all-payer patient panel | Dmand AI Patient Panel Data |
| Training, board certification and memberships | Dmand AI Professional Profile Data |
| Insurance carriers and plan types | Dmand AI Insurance Network Data |
| EHR at each practice site | Dmand AI Technology Install Data |
| Similar physicians | Dmand AI Affiliation Data |
Data last refreshed October 2026Report an inaccuracyRemove my information
FAQ
Frequently asked questions about Dr. James Matthew Diffley
Spotted something out of date? Email hello@dmand.ai and we will check the record. Contact details live in the free trial.
What is Dr. James Matthew Diffley's NPI number?
Dr. James Matthew Diffley's NPI number is 1780974626. It was assigned on April 12, 2011, and it is active in the NPI Registry.
What kind of doctor is Dr. James Matthew Diffley?
Dr. James Matthew Diffley is a pediatrician in Walnut Creek, California. The primary specialty in the NPI Registry is Pediatrics Physician (taxonomy code 208000000X).
Where does Dr. James Matthew Diffley practice?
Dr. Diffley practices at 1425 S Main Street, Walnut Creek, CA 94596. Dr. Diffley's primary practice is Walnut Creek Medical Center in Walnut Creek, California, part of Kaiser Permanente.
What is Dr. James Matthew Diffley's office phone number?
The practice phone on file for Dr. Diffley is (925) 295-4000. Dmand AI also checks direct phone and mobile numbers, available with a free account.
What is Dr. James Matthew Diffley's email address?
Dmand AI checks professional and personal email addresses for Dr. Diffley through healthcare-specific waterfall enrichment. They are available with a free Dmand AI account.
What is Dr. James Matthew Diffley's medical license number?
Dr. Diffley holds California license A114288.
Which hospitals is Dr. James Matthew Diffley affiliated with?
Dr. Diffley practices at Walnut Creek Medical Center in Walnut Creek, California. Dr. Diffley is also affiliated with UCSF Benioff Children's Hospital Oakland.
What medical group is Dr. James Matthew Diffley part of?
Dr. Diffley is linked to The Permanente Medical Group, Inc.
Who does Dr. James Matthew Diffley practice with?
Dmand AI links 18,480 HCPs to Dr. Diffley's primary medical group, 1,005 of them pediatricians. A free account lists them, with verified contacts.
Is Dr. James Matthew Diffley board certified?
Yes. Dr. Diffley is board certified in pediatric hospital medicine by the American Board of Pediatrics.
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Where did Dr. James Matthew Diffley go to medical school?
Dr. Diffley graduated from OU College of Medicine in 2009.
How long has Dr. James Matthew Diffley been practicing?
Dr. Diffley graduated from medical school in 2009, 17 years ago.
What EHR does Dr. James Matthew Diffley's practice use?
Dmand AI tracks the EHR system at Walnut Creek Medical Center and at 1 more affiliated site. The vendor and product are available with a free Dmand AI account.
What insurance does Dr. James Matthew Diffley accept?
Dr. Diffley is in network with 1 carrier, including Kaiser Permanente. EPO plans come from the most carriers, 1. Check the plan with the practice before a visit.
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