Gregory Brennan, M.D.



647 N. Miller Rd

Mansfield, TX 76063

Closed. Opens Mon at 8:30AM

Quick Facts

  • Virtual Telemedicine Visits Available, Call For Details
  • Board Certified Gastroenterologist
  • Currently Accepting New Patients
  • Most Insurance Plans Accepted
  • Performs Colonoscopies

GI Alliance - Mansfield, TX - N. Miller Rd

Gastroenterology in Mansfield, TX

GI Alliance - Mansfield, TX - N. Miller Rd

647 N. Miller Rd

Mansfield, TX 76063

Closed. Opens Mon at 8:30AM


GI Alliance - Mansfield Endoscopy Center - N. Miller Rd

Gastroenterology in Mansfield, TX

GI Alliance - Mansfield Endoscopy Center - N. Miller Rd

647 Miller Road

Ste. 100

Mansfield, TX 76063

Closed. Opens Mon at 8:30AM

Request an Appointment

If you are experiencing a medical emergency, please call 9-1-1. This form is intended for non-urgent appointment requests only. Non-emergency requests will be responded to within 24-48 hours.

About Gregory Brennan, M.D.

Why did you choose to specialize in Gastroenterology?

I choose to specialize in gastroenterology because of the ability to make a real difference in patients lives. The field is advancing rapidly and being able to offer new technology and treatments improves the care for our patients. Building strong relationships with patients and their families is the best part of the field.

Do you have a specialty of interest within GI?

I specialize in all aspects of general gastroenterology and hepatology as well as endoscopy. I have received additional training during my fellowship in the management of inflammatory bowel disease (IBD) and endoscopic resection of large polyps such as endoscopic mucosal resection (EMR).

Some areas of interest I treat include:
Ulcerative colitis, Crohn’s Disease
Colon cancer prevention and screening with colonoscopy
Acid reflux or GERD
Diseases of the liver
Irritable bowel syndrome
Gastrointestinal bleeding and anemia

Where did you study?

Undergraduate School: University of Massachusetts Amherst

Medical School: Tufts University School of Medicine

Residency: University of Texas Southwestern & Parkland

Fellowship: University of California Irvine

What certifications do you hold?

Board Certified in Internal Medicine.

What do you and your family enjoy doing in your spare time?

I enjoy spending time with my family and friends. I enjoy reading and sports.

Awards and Accreditation:

Dr. Brennan was featured as one of “19 fellows to know” on the AGA website ( in 2018 for commitment to advancing GI and patient care through quality improvement projects presented at DDW 2018.

He has published several peer-reviewed papers (on IBD, biliary and pancreatic disorders) in various GI journals including: ACG Case Reports Journal, Cleveland Clinic Journal of Medicine, European Journal of Gastroenterology and Hepatology, Journal of Clinical Gastroenterology, and the journal of the Pancreas.



First visit with Dr. Brennan. He addressed my issue and I came home with a plan to start with. Nice doctor and office staff.

R.G. Google

This was an awesome place! Everybody there were so professional and kind. They took very good care of me. Would definitely recommend to anyone

C.J. Google

I am a new patient of Dr brennan. I was so impressed with him. He actually called to give me results of my blood test. It wasn’t Nurse. It was him. That is so unusual. In today’s times he took his time with me. I really was very impressed.

G.P. Google

Went in for a colonoscopy. Staff was awesome! Very little wait and all the nurses and doctors were friendly and comforting. Highly recommend.

J.M. Google

Dr. Brennan is a very professional, warm, and friendly physician. He answers all your questions and takes his time speaking to you and does a thorough examination. I highly recommend him for your GI needs.

S.L. Google


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