Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 30 days.

DR. JOHN T DUFFIN PHD
NPI 1932184868
Psychologist in Watertown, WI

Active since December 14, 2005PECOS Enrolled
129 HOSPITAL DR, WATERTOWN, WI 53098(920) 262-4800(920) 262-4813 Get Directions Write a Review

NPPES record last updated: July 13, 2026. Verified against the NPPES registry weekly; last sync: August 02, 2026.

About Dr. John T Duffin Phd NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

DR. JOHN T DUFFIN PHD (NPI 1932184868) is an individual psychologist in Watertown, Wisconsin, licensed in Wisconsin (871057) and active in the NPI registry since December 2005. He is enrolled in Medicare PECOS.

NPPES Registry Identity

NPI1932184868
Entity TypeIndividualMale
Primary Taxonomy103T00000X
Provider Legal NameDR. JOHN T DUFFINCredential: PHD
Location Address129 HOSPITAL DRWatertown, WI 53098-3384
Mailing Address129 Hospital DrWatertown, WI 53098-3384 · (920) 262-4800 · Fax (920) 262-4813
Fax(920) 262-4813
Sole ProprietorNo
Enumeration DateDecember 14, 2005
Last NPPES UpdateJuly 13, 2026
NPI 1932184868 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

Primary SpecialtyPsychologistBehavioral Health & Social Service Providers
Taxonomy Code103T00000X
License Licensed in WI · 871057
Definition
A psychologist is an individual who is licensed to practice psychology which is defined as the observation, description, evaluation, interpretation, and modification of human behavior by the application of psychological principles, methods, and procedures, for the purpose of preventing or eliminating symptomatic, maladaptive, or undesired behavior and of enhancing interpersonal relationships, work and life adjustment, personal effectiveness, behavioral health, and mental health. The practice of psychology includes, but is not limited to, psychological testing and the evaluation or assessment of personal characteristics, such as intelligence, personality, abilities, interests, aptitudes, and neuropsychological functioning; counseling, psychoanalysis, psychotherapy, hypnosis, biofeedback, and behavior analysis and therapy; diagnosis and treatment of mental and emotional disorder or disability, alcoholism and substance abuse, disorders of habit or conduct, as well as of the psychological aspects of physical illness, accident, injury, or disability; and psycheducational evaluation, therapy, remediation, and consultation. Psychological services may be rendered to individuals, families, groups and the public.
129 HOSPITAL DR, Watertown, WI 53098

Other Identifiers 1

Medicaid3909110WI

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, and ordering and referring status from the CMS PECOS system.

Medicare Enrollment Status

Enrolled in Medicare (PECOS)

Dr. John T Duffin Phd is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Eligible to Order & Refer Part B Labs & Imaging Durable Medical Equipment Home Health Agency Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Other Providers at the Same Location NPPES 9

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

Psychiatry & Neurology (Psychiatry)
129 HOSPITAL DR
WATERTOWN, WI 53098
Psychiatry & Neurology (Psychiatry)
129 HOSPITAL DR
WATERTOWN, WI 53098
Psychiatry & Neurology (Psychiatry)
129 HOSPITAL DR
WATERTOWN, WI 53098
Clinic/Center (Mental Health (Including Community Mental Health Center))
129 HOSPITAL DR
WATERTOWN, WI 53098
Clinic/Center (Adult Mental Health)
129 HOSPITAL DR
WATERTOWN, WI 53098
Social Worker (Clinical)
129 HOSPITAL DR
WATERTOWN, WI 53098
Psychologist
129 HOSPITAL DR
WATERTOWN, WI 53098
Counselor
129 HOSPITAL DR
WATERTOWN, WI 53098

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is John Duffin's NPI number?

The NPI number for John Duffin is 1932184868. It was assigned to this individual provider in the NPPES registry on December 14, 2005.

Where is John Duffin located?

John Duffin practices at 129 Hospital Dr, Watertown, WI 53098. The listed phone number is (920) 262-4800.

What is John Duffin's specialty?

The primary specialty registered for this NPI is Psychologist with taxonomy code 103T00000X.

Is John Duffin enrolled in Medicare?

Yes. John Duffin is registered in the Medicare PECOS enrollment system.

When was this NPI record last updated?

The NPPES record for John Duffin was last updated on July 13, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 22 days ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.