Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
NPIDirectory

Dennis S O'Brien, PAC

Individual provider Medical Physician Assistant · NPI 1407895956

Dennis S O'Brien, PAC is a Physician Assistant in Springfield, Massachusetts. Qualified in 2004, 22 years ago. Practices with Baystate Medical Practices Inc, a 1,346-clinician group and accepts Medicare assignment. Licensed in Massachusetts.

Years since qualifying
22
Licensed in
MA
In the registry since
2006
What do these letters mean?
PAC — Physician Assistant, Certified
A physician assistant holding current national certification; usually written PA-C.

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Practice location Address checks out

3300 Main St 3rd Fl Ste C&d
Springfield, MA 01199-1619
Phone: (413) 794-7033
Fax: (413) 794-7297
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Medical Physician Assistant (primary) Taxonomy 363AM0700X · Licence PA4779 (MA)

Record details

NPI number1407895956
Entity typeIndividual (Type 1)
GenderMale
Credentials PAC
Sole proprietorNo
NPI enumeratedJune 6, 2006
Last updated in NPPESDecember 16, 2019
Certification dateDecember 16, 2019

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyPHYSICIAN ASSISTANT
Medical schoolOTHER
Graduated 2004 (22 years in practice)
Group practice Baystate Medical Practices Inc — 1346 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations2 on file with Medicare

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