Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
Ronald R Castonguay, MD
Specialist in Fresno, CA · enumerated 2007.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1154467074
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Registry record
Entity type Individual (Type 1)
Name Ronald R Castonguay
Credential MD
Sex Male
Practice address 7255 N Cedar Ave, Fresno, CA, 93720
Phone (559) 431-5353
Enumeration date Jan 29, 2007
Last updated in NPPES Jun 11, 2009
Taxonomy & licenses
MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure.
About the MD credential
Other identifiers
| Identifier | Type | State | Issuer |
|---|---|---|---|
| ZZZ17834Z | Other | CA | BLUE SHIELD |
| 00A551670 | Medicaid | CA | - |
| 184324800 | Other | CA | USDL |
What is an NPI number?
A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.
Frequently asked questions
What specialty is Ronald Castonguay?
Ronald Castonguay is registered in NPPES with the primary taxonomy of Specialist. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.
Is this the official NPI registry?
No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.
Other providers at this practice address
Browse all → Arthroscopic Surgery Associates Corporation Orthopaedic Surgery Physician · Fresno, CA NPI 1881603256 Robert Mochizuki Orthopaedic Surgery Physician · Fresno, CA NPI 1023028883 Ronald M Castonguay MD Inc Specialist · Fresno, CA NPI 1770629701 Amitabh Goswami Interventional Pain Medicine Physician · Fresno, CA NPI 1447451539 Amitabh U Goswami Do Inc Physical Medicine & Rehabilitation Physician · Fresno, CA NPI 1598213027
Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2009-06-11.