Type 2 · Organization ✓ Active NPI ✓ Valid NPI checksum

Willow Aba Services

Q: What is the NPI number for Willow Aba Services?

The NPI for Willow Aba Services is 1205466612, a Type 2 (organization) record in the CMS NPPES registry.

Behavior Analyst in Littleton, CO · enumerated 2020 · authorized official Tanner Sierks Sierks, Owner.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1205466612

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Registry record

Entity type Organization (Type 2)

Legal business name Willow Aba Services

Practice address 8000 S Lincoln St Ste 10, Littleton, CO, 80122

Phone (720) 316-7614

Fax (720) 316-7614

Enumeration date Jan 24, 2020

Last updated in NPPES Sep 26, 2025

Taxonomy & classification

103K00000X Behavior Analyst Behavioral Health & Social Service Providers Primary

Authorized official

Name Tanner Sierks Sierks

Title Owner

Phone (720) 319-7614

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

What is the NPI number for Willow Aba Services?

The NPI for Willow Aba Services is 1205466612, a Type 2 (organization) record in the CMS NPPES registry.

Who is the authorized official for Willow Aba Services?

NPPES lists Tanner Sierks Sierks (Owner) as the authorized official for this organization.

Providers at this address

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2025-09-26.