Gregory Brennan, M.D.



647 N. Miller Rd

Mansfield, TX 76063

Open today 8:30AM - 4:30PM

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

Open today 8:30AM - 4:30PM

Request 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.



Great Doctor and staff , thy took every step to make sure I was comfortable and everything was completed correctly.

S.L. Google

Dr Brennan was very attentive to my concerns and started testing right away. Appointment tomorrow to see what course of action is needed. He was so kind. Really like him helping me.

L.P. Google

Entire staff was welcoming and provide excellent service.

J.J. Google

Very understanding and attentive of my issues

M.N. Google

The procedure couldn't have went any better. Dr. Brennan, the nurse , and staff went above and beyond to put me at ease, answering all of my questions and making sure I was comfortable. I was in and out of there in 1 hour. I definitely will be going there my next time around.

S. Google


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