Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
Dr. Margaret Janina Slowik, OD
Optometrist in La Grange, IL · enumerated 2007.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1124222591
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Registry record
Entity type Individual (Type 1)
Name Dr. Margaret Janina Slowik
Credential OD
Sex Female
Practice address 100 W Calendar Ave, La Grange, IL, 60525
Phone (708) 354-0500
Enumeration date Jun 12, 2007
Last updated in NPPES Jan 25, 2024
Taxonomy & licenses
OD · Doctor of Optometry: A licensed optometrist providing primary vision care, eye exams, and corrective lenses.
About the OD credential
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.
Frequently asked questions
Where does Margaret Slowik practice?
The practice location on file with NPPES is in La Grange, IL. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Margaret Slowik?
The National Provider Identifier (NPI) for Margaret Slowik is 1124222591, a Type 1 (individual) record in the CMS NPPES registry.
Other providers at this practice address
Browse all →Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2024-01-25.