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

Gregorio J. Guillen, MD

Individual provider Geriatric Medicine (Internal Medicine) Physician · NPI 1538252226

Gregorio J. Guillen, MD is an Internal Medicine in Perth Amboy, New Jersey. Qualified in 1982, 44 years ago. Practices as a sole proprietor and accepts Medicare assignment. Licensed in New Jersey.

Years since qualifying
44
Licensed in
NJ
In the registry since
2006
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

See every abbreviation used in this directory →

Practice location Address checks out

400 State St Ste 2
Perth Amboy, NJ 08861
Phone: (732) 442-6020
Fax: (732) 442-1995
Show map & directions

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Geriatric Medicine (Internal Medicine) Physician (primary) Taxonomy 207RG0300X · Licence MA56159 (NJ)

Record details

NPI number1538252226
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorYes
NPI enumeratedOctober 2, 2006
Last updated in NPPESAugust 6, 2013

Medicare enrollment

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

Medicare specialtyINTERNAL MEDICINE
Also practisesGERIATRIC MEDICINE
Medical schoolOTHER
Graduated 1982 (44 years in practice)
Accepts Medicare assignment Yes — accepts the Medicare-approved amount