LAKE COUNTY INTERNAL MEDICINE ASSOCIATES, LLC
NPI 1154686525
Internal Medicine in Long Grove, IL

Q: What is Lake County Internal Medicine Associates, LLC's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Active since July 11, 2012

5911 KILDEER CT, LONG GROVE, IL 60047(847) 478-5108 Get Directions Write a Review

NPPES record last updated: July 11, 2012. Verified against the NPPES registry weekly; last sync: October 18, 2026.

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About Lake County Internal Medicine Associates, Llc NPPES

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

LAKE COUNTY INTERNAL MEDICINE ASSOCIATES, LLC (NPI 1154686525) is a healthcare organization registered as an internal medicine in Long Grove, Illinois and active in the NPI registry since July 2012. The organization lists Mariusz Milejczyk, President, as its authorized official.

NPPES Registry Identity

NPI1154686525

Entity TypeOrganization

Primary Taxonomy207R00000X

Legal Business NameLAKE COUNTY INTERNAL MEDICINE ASSOCIATES, LLC

Location Address5911 KILDEER CTLong Grove, IL 60047-5052

Mailing Address5911 Kildeer CtLong Grove, IL 60047-5052

Phone(847) 478-5108

Organization SubpartNo

Authorized OfficialMariusz MilejczykPresident · (847) 478-5108

Enumeration DateJuly 11, 2012

✔ NPI 1154686525 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians

Taxonomy Code207R00000X

Definition

A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.

5911 KILDEER CT, Long Grove, IL 60047

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Group Practice 1

Group TaxonomyThis provdier is a business group of one or more individual practitioners, all of who practice with the same area of specialization.193400000X SINGLE SPECIALTY GROUP

Medicare Participation & PECOS CMS

Medicare enrollment and the clinicians who bill Medicare through this organization, from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Lake County Internal Medicine Associates, Llc is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Clinicians Billing Medicare Through This Organization

Medicare enrollment records show 1 clinician reassigns Medicare billing to Lake County Internal Medicine Associates, LLC, which bills Medicare for the services this clinician delivers.

Clinician (1)

Mariusz Milejczyk, MD

Internal Medicine

NPI 1467598235

1880 W WINCHESTER RD STE 106
Libertyville, IL 60048

(847) 367-4277

✔ PECOS✔ Accepts Medicare6.3 mi

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

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 Lake County Internal Medicine Associates, LLC's NPI number?

The NPI number for Lake County Internal Medicine Associates, LLC is 1154686525. It was assigned to this organization in the NPPES registry on July 11, 2012.

Where is Lake County Internal Medicine Associates, LLC located?

Lake County Internal Medicine Associates, LLC is located at 5911 Kildeer Ct, Long Grove, IL 60047. The listed phone number is (847) 478-5108.

What is Lake County Internal Medicine Associates, LLC's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Is Lake County Internal Medicine Associates, LLC enrolled in Medicare?

Yes. Lake County Internal Medicine Associates, LLC is registered in the Medicare PECOS enrollment system.

How many clinicians bill Medicare through Lake County Internal Medicine Associates, LLC?

According to the CMS Revalidation Reassignment List (October 2026 release), 1 clinician (Internal Medicine) reassigns their Medicare billing to Lake County Internal Medicine Associates, LLC. A reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for the clinician's services. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

When was this NPI record last updated?

The NPPES record for Lake County Internal Medicine Associates, LLC was last updated on July 11, 2012. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 14 years 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.