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MAZIYAR MIRHOSSEINI M.D.
NPI 1508870809
Internal Medicine in Downers Grove, IL

Active since July 29, 2006PECOS EnrolledAccepts Medicare Assignment
3815 HIGHLAND AVE, DOWNERS GROVE, IL 60515(312) 609-0300 Get Directions Write a Review

NPPES record last updated: December 17, 2021. Verified against the NPPES registry weekly; last sync: November 01, 2026.

About Maziyar Mirhosseini M.d. NPPES

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

MAZIYAR MIRHOSSEINI M.D. (NPI 1508870809) is an individual internal medicine provider in Downers Grove, Illinois, licensed in Illinois (036-110389) and active in the NPI registry since July 2006. He is enrolled in Medicare PECOS, is affiliated with Advocate Good Samaritan Hospital, and is a graduate of Other (1996).

NPPES Registry Identity

NPI1508870809
Entity TypeIndividualMale
Primary Taxonomy207R00000X
Provider Legal NameMAZIYAR MIRHOSSEINICredential: M.D.
Location Address3815 HIGHLAND AVEDowners Grove, IL 60515-1500
Mailing Address2311 W 22nd St, Suite 202Oak Brook, IL 60523-1225
Phone(312) 609-0300
Sole ProprietorNo
Medical School CMSOtherGraduated 1996
Enumeration DateJuly 29, 2006
Last NPPES UpdateDecember 17, 2021
NPPES CertifiedDecember 17, 2021
✔ NPI 1508870809 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207R00000X
License✔ Licensed in IL · 036-110389
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.
3815 HIGHLAND AVE, Downers Grove, IL 60515
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Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Maziyar Mirhosseini M.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 ID1557323730
PECOS Enrollment IDI20041029000902
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.

Medicare Billing Reassignment

Medicare enrollment records show Maziyar Mirhosseini reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Advocate Health And Hospitals Corporation
0.1 mi
Cardiovascular Disease
3825 HIGHLAND AVE, TOWER 2 SUITE 400
Downers Grove, IL 60515
  • Reassigned Medicare billing, Illinois enrollment
  • 4,870 clinicians in this Medicare group
NPI 1285903849 (630) 719-4799

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

Areas of Expertise CMS Part B claims 7

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.

Subsequent hospital care with moderate levelof medical decision making, if using time, at least 50 minutes 99233
Follow-up hospital inpatient care per day typically involves a 35-minute check-up by your healthcare provider. This service includes monitoring your health progress, adjusting your treatment plan if needed, and answering any questions you may have about your condition or care.
393 services147 patients
Hospital discharge day management, more than 30 minutes 99239
Hospital discharge day management over 30 minutes involves a detailed process to ensure a smooth transition from hospital to home. It includes final examinations, discussion of your hospital stay, post-discharge instructions, and coordinating follow-up care.
220 services199 patients
Initial hospital care with moderate level of medical decision making, if using time, at least 75 minutes 99223
Initial hospital inpatient care per day, typically 70 minutes, refers to the daily medical service provided to patients admitted to the hospital. This includes a comprehensive evaluation, diagnosis, treatment plan, and monitoring of your health condition. It ensures your well-being during your hospital stay.
177 services167 patients
Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes 99232
Follow-up hospital inpatient care involves daily check-ups while you're admitted in the hospital. Typically, a healthcare provider spends about 25 minutes each day reviewing your condition, adjusting treatment if needed, and answering any questions you might have.
79 services50 patients
Initial hospital care with straightforward or low-level medical decision making, if using time, at least 55 minutes 99222
Initial hospital inpatient care is a service where a healthcare provider spends about 50 minutes per day overseeing your care while you're admitted in the hospital. This includes reviewing your health status, planning your treatment, and ensuring your safety and comfort.
35 services34 patients
Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more 99214
This is a routine check-up for patients who have previously visited our clinic. It involves a comprehensive review of your health and any ongoing treatments. The consultation lasts between 30-39 minutes, allowing enough time to discuss any concerns.
14 services12 patients

Hospital Affiliations CMS Care Compare

Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.

Advocate Good Samaritan Hospital

Acute Care Hospitals · Downers Grove, IL
3/5 CMS rating
OwnershipVoluntary non-profit - Private
CMS Certification Number140288
Location3815 Highland AvenueDowners Grove, IL 60515 · Du Page County
Emergency services Birthing friendly

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 60515 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient
$137.43 typical visit price
range $59.81 – $181.38
Typical copayment $34.35 (range $14.95 – $45.34)
Most-billed visit code 99204
Established Patient
$105.07 typical visit price
range $19.15 – $147.12
Typical copayment $26.26 (range $4.78 – $36.78)
Most-billed visit code 99214
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Other Providers at the Same Location NPPES 20

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

STEPHANIE WOLFF PA-C
Physician Assistant
3815 HIGHLAND AVE
DOWNERS GROVE, IL 60515
Dupage County (630) 275-5900
ABIGAIL MAZUREK
Physical Therapist
3815 HIGHLAND AVE
DOWNERS GROVE, IL 60515
Dupage County (630) 275-5900
DR. MICHAEL J IWANICKI D.O.
Surgery
3815 HIGHLAND AVE, TOWER 2, SUITE 107
DOWNERS GROVE, IL 60515
Dupage County (630) 275-7800
TRAUMA AND SURGICAL SPECIALISTS OF DUPAGE, LLC
Surgery
3815 HIGHLAND AVE, TOWER 2, SUITE 107
DOWNERS GROVE, IL 60515
Dupage County (630) 275-7800
DR. JUSTIN GRIFFITH MILLER M.D.
Thoracic Surgery (Cardiothoracic Vascular Surgery)
3815 HIGHLAND AVE
DOWNERS GROVE, IL 60515
Dupage County (630) 324-7913
ZACHARY JOHN BASTIAN M.D.
Anesthesiology
3815 HIGHLAND AVE
DOWNERS GROVE, IL 60515
Dupage County (630) 275-5900
MANISA BAKER APN
Clinical Nurse Specialist (Acute Care)
3815 HIGHLAND AVE
DOWNERS GROVE, IL 60515
Dupage County (630) 275-5900
MARY SUE DAILEY APRN
Clinical Nurse Specialist (Adult Health)
3815 HIGHLAND AVE
DOWNERS GROVE, IL 60515
Dupage County (630) 275-5900

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 Maziyar Mirhosseini's NPI number?

The NPI number for Maziyar Mirhosseini is 1508870809. It was assigned to this individual provider in the NPPES registry on July 29, 2006.

Where is Maziyar Mirhosseini located?

Maziyar Mirhosseini practices at 3815 Highland Ave, Downers Grove, IL 60515. The listed phone number is (312) 609-0300.

What is Maziyar Mirhosseini's specialty?

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

Is Maziyar Mirhosseini enrolled in Medicare?

Yes. Maziyar Mirhosseini 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.

Which organization bills Medicare for Maziyar Mirhosseini's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Maziyar Mirhosseini reassigns Medicare benefits to Advocate Health And Hospitals Corporation (Downers Grove, IL). The 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 Maziyar Mirhosseini's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

Is Maziyar Mirhosseini affiliated with any hospitals?

According to CMS data, Maziyar Mirhosseini is affiliated with Advocate Good Samaritan Hospital.

When was this NPI record last updated?

The NPPES record for Maziyar Mirhosseini was last updated on December 17, 2021. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 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.