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

John Gregory Duffy MD, APC

Organization Psychiatry Physician · NPI 1093985137

John Gregory Duffy MD, APC is a Psychiatry Physician in Tustin, California. Licensed in California. Registered with an NPI since 2008.

Licensed in
CA
In the registry since
2008
What do these letters mean?
APC — A professional corporation
A form of business registration, not a clinical qualification.

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Practice location Address checks out

17821 E 17st Ste 165
Tustin, CA 92780-2136
Phone: (714) 669-3158
Fax: (714) 669-3198
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Psychiatry Physician (primary) Taxonomy 2084P0800X · Licence A054948 (CA)

Record details

NPI number1093985137
Entity typeOrganization (Type 2)
Organization subpartNo
Authorized official John Duffy — President · (714) 669-3198
NPI enumeratedMarch 5, 2008
Last updated in NPPESMarch 11, 2008
Mailing address17821 E 17st, Suite 165, Tustin, CA 92780-2136

Other providers in Tustin