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DR. WILLAIM ALLEN DECKER PH. D.
NPI 1033234950
Psychologist - Cognitive & Behavioral in Alexandria, VA

Active since March 20, 2007PECOS EnrolledAccepts Medicare Assignment
1423 POWHATAN ST, SUITE 8, ALEXANDRIA, VA 22314(703) 836-3678(703) 836-2667 Get Directions Write a Review

NPPES record last updated: September 11, 2025. Verified against the NPPES registry weekly; last sync: August 09, 2026.

About Dr. Willaim Allen Decker Ph. D. NPPES

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

DR. WILLAIM ALLEN DECKER PH. D. (NPI 1033234950) is an individual cognitive & behavioral provider in Alexandria, Virginia, licensed in Virginia (0810002331) and active in the NPI registry since March 2007. He is enrolled in Medicare PECOS and is a graduate of Other (1975).

NPPES Registry Identity

NPI1033234950
Entity TypeIndividualMale
Primary Taxonomy103TB0200X
Provider Legal NameDR. WILLAIM ALLEN DECKERCredential: PH. D.
Location Address1423 POWHATAN ST, SUITE 8Alexandria, VA 22314-1389
Mailing Address1423 Powhatan St, Suite 7Alexandria, VA 22314-1389 · (703) 836-3678 · Fax (703) 836-2667
Phone(703) 836-3678
Fax(703) 836-2667
Sole ProprietorYes
Medical School CMSOtherGraduated 1975
Enumeration DateMarch 20, 2007
Last NPPES UpdateSeptember 11, 2025
✔ NPI 1033234950 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 4

★ Primary SpecialtyPsychologist · Cognitive & BehavioralBehavioral Health & Social Service Providers
Taxonomy Code103TB0200X
License✔ Licensed in VA · 0810002331
Definition
A psychologist who reflects an experimental-clinical approach distinguished by use of principles of human learning and development and theories of cognitive processing to promote meaningful change in maladaptive human behavior and thinking.
Also ListedClinical NeuropsychologistTaxonomy 103G00000X · License 0810002331 (VA)
Also ListedPsychologist · ClinicalTaxonomy 103TC0700X · License 0810002331 (VA)
Also ListedPsychologist · Health ServiceTaxonomy 103TH0100X · License 0810002331 (VA)
1423 POWHATAN ST, Alexandria, VA 22314
Open in Google Maps ↗

Other Identifiers 1

OtherA7860001MD · Bcbs Nca Carefirst

Medicare Participation & PECOS CMS

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

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Dr. Willaim Allen Decker Ph. D. is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID6204987985
PECOS Enrollment IDI20100202000101
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.

Areas of Expertise CMS Part B claims 3

Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.

Psychotherapy, 1 hour 90837
Psychotherapy is a therapeutic interaction or treatment between a trained professional and a patient. In a 1-hour session, you'll talk about your feelings, thoughts, and behaviors to help identify and manage mental health issues. This process aids in personal growth, healing, and improved well-being.
646 services21 patients
Psychotherapy, 30 minutes 90832
Psychotherapy is a therapeutic interaction or treatment between a trained professional and a patient. In a 30-minute session, the therapist helps you explore feelings, thoughts, and behaviors to better understand yourself and manage life's challenges.
82 services12 patients
Psychotherapy, 45 minutes 90834
Psychotherapy is a treatment method where you converse with a therapist about your thoughts, feelings, and behaviors. In a 45-minute session, the therapist assists you in understanding and managing your mental health concerns, improving emotional wellness, and promoting personal growth.
69 services18 patients

Other Providers at the Same Location NPPES 2

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

DR. JOSEPH S HENDERSON DC
Chiropractor
1423 POWHATAN ST, SUITE 7
ALEXANDRIA, VA 22314
Alexandria City (703) 739-7650
MR. GARY HANKINS L.C.S.W
Social Worker (Clinical)
1423 POWHATAN ST
ALEXANDRIA, VA 22314
Alexandria City (202) 239-5924

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 Willaim Decker's NPI number?

The NPI number for Willaim Decker is 1033234950. It was assigned to this individual provider in the NPPES registry on March 20, 2007.

Where is Willaim Decker located?

Willaim Decker practices at 1423 Powhatan St Suite 8, Alexandria, VA 22314. The listed phone number is (703) 836-3678.

What is Willaim Decker's specialty?

The primary specialty registered for this NPI is Psychologist, specializing in Cognitive & Behavioral, with taxonomy code 103TB0200X.

Is Willaim Decker enrolled in Medicare?

Yes. Willaim Decker is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

When was this NPI record last updated?

The NPPES record for Willaim Decker was last updated on September 11, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 11 months 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.