Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Catherine Lloyd O'Brien, M.D.

Allergy & Immunology Physician in Wareham, MA · enumerated 2006.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1205800810

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Registry record

Entity type Individual (Type 1)

Name Dr. Catherine Lloyd O'Brien

Credential M.D.

Sex Female

Practice address 53 Marion Rd, Suite 7, Wareham, MA, 02571

Phone (508) 295-5572

Fax (508) 291-2777

Enumeration date Feb 13, 2006

Last updated in NPPES Sep 26, 2007

Taxonomy & licenses

207K00000X Allergy & Immunology Physician Allopathic & Osteopathic Physicians · License 34833 (MA) Primary

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
2046229	Medicaid	MA	-
M08500	Other	MA	BLUECROSS BLUESHIELD
708925	Other	MA	TUFTS HEALTH INSURANCE
2237497	Other	MA	UNITED HEALTHCARE

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.

Read the full guide → Validate an NPI →

Frequently asked questions

What is the NPI number for Catherine O'Brien?

The National Provider Identifier (NPI) for Catherine O'Brien is 1205800810, a Type 1 (individual) record in the CMS NPPES registry.

Where does Catherine O'Brien practice?

The practice location on file with NPPES is in Wareham, MA. Providers can have multiple locations; NPPES lists the primary practice address.

Other providers at this practice address

Browse all →

Jennifer Russell Pediatrics Physician · Wareham, MA NPI 1518925452 Jenna Smith Clinical Social Worker · Wareham, MA NPI 1902810930 John Conway Pediatrics Physician · Wareham, MA NPI 1669575809 Jason Reynolds Pediatrics Physician · Wareham, MA NPI 1184727323 Amanda Conley Pediatric Nurse Practitioner · Wareham, MA NPI 1417263989 Ann Marie Sylvester Pediatric Nurse Practitioner · Wareham, MA NPI 1154796936 Kaitlyn Gibson Pediatric Nurse Practitioner · Wareham, MA NPI 1154878247 Catelyn Rueger Pediatrics Physician · Wareham, MA NPI 1134708092

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-09-26.