Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

Gregory W Gerritsen, PHD

Individual provider Clinical Psychologist · NPI 1083795686

Gregory W Gerritsen, PHD is a Clinical Psychologist in Boulder, Colorado. Practices as a sole proprietor. Licensed in Colorado.

Licensed in
CO
In the registry since
2006
What do these letters mean?
PHD — Doctor of Philosophy
A research doctorate. In healthcare it usually sits alongside a clinical licence.

See every abbreviation used in this directory →

Claim this listing Report a problem Suggest an edit

Practice location Address checks out

2501 Walnut St Ste 202
Boulder, CO 80302-5751 Not confirmed with CMS for 19 years — call before visiting
Phone: (303) 473-4433
Fax: (303) 499-2217
Show map & directions

Directions in Google Maps · Apple Maps · OpenStreetMap

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

Specialties & licences

Clinical Psychologist (primary) Taxonomy 103TC0700X · Licence 1209 (CO)

Record details

NPI number1083795686
Entity typeIndividual (Type 1)
GenderMale
Credentials PHD
Sole proprietorYes
NPI enumeratedOctober 18, 2006
Last updated in NPPESOctober 23, 2007

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients13
Services billed 109 a service is one billed item, such as a visit, a test or a procedure
Average patient age72

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Other providers in Boulder