Dr. Jacek Zajac, MD | Lombard, IL | Endocrinology

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Dr. Jacek Zajac specializes in endocrinology, diabetes and metabolism, as well as internal medicine. He earned his medical degree from Jagiellonian University Medical College and completed his residency at Beth Israel Medical Center. With 35 years of experience in practice, Dr. Zajac brings extensive knowledge to the management of complex hormonal and metabolic conditions. He is fluent in both English and Polish.

Dr. Zajac practices at multiple locations throughout the Chicago area, including Lombard and Elmhurst, Illinois, with hospital affiliations at Elmhurst Memorial Hospital and Advocate Good Samaritan Hospital. He focuses on treating patients with type 2 diabetes and helping children and teens manage diabetes effectively. His expertise includes performing thyroid hormone testing and thyroid-stimulating hormone evaluations to assess endocrine function. Patients have given him an average rating of 3.5 on Vitals.

AI-generated from data on this provider profile.

accepting new patients
3.5

24 Ratings
35 years of experience
32 insurance plans accepted
speaks English, Polish
Beth Israel Medical Center
8 written reviews
2 specialties
14 areas of expertise
2 board certifications
1 hospital affiliation
3 office locations
Male

24 ratings & reviews

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Showing 1 to 8 of 8 reviews

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The phone number here doesn't work. I get a busy signal or an error message, please contact me.

October 27th, 2025

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I have been with for almost a year. All he does is send you for tests and more tests. He doesn’t help you with symptoms at all. “ well if your levels were 3 x times “ then.... Really! High is high. Our dogs get better care than what I have been getting. Even the other Drs didnt want to say anything... but said well do this test if he asked. Looking for another Dr!!

April 5th, 2018

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While he is an excellent doctor, he is against communication. His office will not allow messages. They have limited hours, and you only get a answering service that simply states they will not take a message. There is no way to communicate with the office. I saw him three weeks ago. His office never submitted a prescription for me, and no one told me I should be taking a new med. It appeared on my list of medicines on the website, so that is how I found out. I keep calling, but only get an answering service that tells me to call back. I do not recommend this practice. If you want to try this office, call a few times and see what happens on communication.

June 14th, 2017

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His office staff is very unprofessional and NEVER EVER answer the phones. Noattorney the time of day they will put on the answering service. When trying to simply get my medical records to see a doctor whose staff actually answers the phones, I called, faxed twice and still don't have my medical records. UGGGHHH!

November 24th, 2015

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Have to wait weeks or months for an appointment and then they cancel two days before. I haven't been able to see him for a year now because of this. Had no choice but to switch doctors.

May 12th, 2011

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If you want someone that is busy.(10-12 weeks to get first appointment) If you want someone who never calls you back.If you want someone that just does'nt care. This guy is for you!

March 8th, 2011

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Monday hours trying to make a follow up appt after surgery. Answering service onduty until 11:00 but, when calling back at 11:11 phones not taken back. Next call lines was busy. Then at 12:16 out to lunch until 1:30....Really

March 7th, 2011

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I see Dr. Zajac on a regular basis, and not once have I gone and not waited an hour to see him. He is a wonderful doctor, but needs to get rid of his receptionists who are regularly rude and update his scheduling.

December 21st, 2009

Endocrinology Associates

2500 S Highland Ave Ste 104Lombard, IL 60148

Tel: (630) 629-3610

Mon9:00 am - 4:30 pm

Tue9:00 am - 4:30 pm

Wed9:00 am - 4:30 pm

Thu9:00 am - 4:30 pm

Fri9:00 am - 4:30 pm

SatClosed

SunClosed

Elmhurst Memorial Hospital

155 E Brush Hill RdElmhurst, IL 60126

Tel: (331) 221-1000

Advocate Good Samaritan Hospital

3815 Highland AveDowners Grove, IL 60515

Tel: (630) 275-5900


Dr. Jacek Zajac, MD	Dr. Bekir Suveyd	Dr. Oluwatomi Oluwagbemisola Asemota	Dr. Andrea Lynn Mccoy
Endocrinology, Diabetes & Metabolism	Endocrinology, Diabetes & Metabolism	Endocrinology, Diabetes & Metabolism	Endocrinology, Diabetes & Metabolism
Accepts New Patients	Accepts New Patients	Accepts New Patients	Accepts New Patients
3.5 (24 Ratings)	0 (0 Ratings)	0 (0 Ratings)	0 (0 Ratings)
35 Years of Experience	11 Years of Experience	12 Years of Experience
No Virtual Visit Option	Virtual Visit Available	Virtual Visit Available	Virtual Visit Available
Speaks English, Polish	Speaks English, Arabic	Speaks English
Lombard , IL	CHICAGO , IL	CHICAGO , IL	CHICAGO , IL
Med School: Jagiellonian University Medical College	Med School: Alfaisal University College Of Medicine	Med School: University Of Ibadan College Of Medicine
Current Profile	View Profile	View Profile	View Profile

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Acromegaly
Addison Disease
Cushing Disease
Diabetes
Diabetes (Types I & II)
Diabetes Mellitus, Type 1
Fatigue
Gland Issues
Hormones
Hyperthyroidism
Hypopituitarism
Hypothyroidism
Internal Medicine
Obesity

MEDICAL LICENSE

Medical Doctor, Illinois, 2026, Active

EDUCATION & TRAINING

Residency

Beth Israel Medical Center

Medical School

Jagiellonian University Medical CollegeGraduated in 1991

Cindy S Bestrycki
Internal Medicine
| Glendale Heights, IL
(0)
Dr. David F Saldanha, MD
Vascular & Interventional Radiology
19 Years Exp | Rockford, IL
(7)
Dr. Juanita Mora, MD
Allergy & Immunology
23 Years Exp | Chicago, IL
(5)
Dr. Asif Hussain, MD
Pediatrics
26 Years Exp | Oswego, IL
(0)
Dr. Julie Lynn Fitzgerald, MD
Pediatrics
28 Years Exp | Maywood, IL
(0)
Dr. Nadia Haider, MD
Anesthesiology
22 Years Exp | Chicago, IL
(0)
Dr. Stephanie Beth Hampel Kelly, MD
Pediatrics
| Chicago, IL
(0)
Dr. Elizabeth Louise Wiley, MD
Pathology
52 Years Exp | CHICAGO, IL
(0)
Dr. Neelima Divakaran, MD
Hospital Medicine
22 Years Exp | Evanston, IL
(0)
Dr. Douglas Jackson, MD
Emergency Medicine
49 Years Exp | ELGIN, IL
(2)

How can I make an appointment with Dr. Jacek Zajac?: You can find contact information for Dr. Jacek Zajac here on Vitals.
Is Dr. Jacek Zajac accepting new patients?: Dr. Jacek Zajac is accepting new patients on Vitals. View Dr. Jacek Zajac's profile on Vitals to make an appointment.
Does Dr. Jacek Zajac accept my insurance?: You can see the insurance plans that Dr. Jacek Zajac accepts on their Vitals profile.
Does Dr. Jacek Zajac accept virtual/telehealth appointments?: Dr. Jacek Zajac has not indicated that they accept virtual/teleheatlh appointments. Contact their office through their Vitals profile to check for availability.
Which hospitals is Dr. Jacek Zajac affiliated with?: Dr. Jacek Zajac is affiliated with Elmhurst Memorial Hospital.

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