Type 2 · Organization ✓ Active NPI ✓ Valid NPI checksum

Donna Lettieri-Marks, Psy.D., Ltd

Adult Mental Health Clinic/Center in Naperville, IL · enumerated 2009 · authorized official Donna Lettieri-Marks, Clinical Psychologist/Owner.

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

National Provider Identifier

1649418518

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Registry record

Entity type Organization (Type 2)

Legal business name Donna Lettieri-Marks, Psy.D., Ltd

Practice address 55 S Main St, Suite 371, Naperville, IL, 60540

Phone (630) 904-6610

Fax (630) 544-3429

Enumeration date Jan 29, 2009

Last updated in NPPES Jan 29, 2009

Taxonomy & classification

261QM0850X Adult Mental Health Clinic/Center Ambulatory Health Care Facilities · License 071-005423 (IL) Primary

Authorized official

Name Donna Lettieri-Marks

Title Clinical Psychologist/Owner

Phone (630) 904-6610

Other identifiers

Identifier	Type	State	Issuer
1346233665	Other	—	NPI (INDIVIDUAL TYPE I NUMBER)
357980	Other	IL	MEDICARE

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

Where is Donna Lettieri-Marks, Psy.D., Ltd located?

The practice location on file with NPPES is in Naperville, IL.

How current is this record?

Data comes from the CMS NPPES public dissemination file; this record was last updated in NPPES on 2009-01-29. Verify at npiregistry.cms.hhs.gov.

Providers at this address

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2009-01-29.