Dr. Ali Khalessi, MD
Board-Certified Gastroenterologist
Expertise & Credentials
- Faculty member at NewYork-Presbyterian/Weill Cornell Medical Center
- Double board-certified in Internal Medicine and Gastroenterology by the American Board of Internal Medicine (ABIM)
- Doctor of Medicine from NYU Grossman School of Medicine
- Internal Medicine Residency at NYU Langone Medical Center
- Gastroenterology Fellowship at Rutgers, Chief Fellow
- Focus areas include inflammatory bowel disease (Crohn's disease and ulcerative colitis), colon cancer screening, GERD and Barrett's esophagus, irritable bowel syndrome (IBS), and hemorrhoid treatment
Union Square
Primary Location | New York Locations 55 W 17th Street, Ste 102New York, NY 10011 (212) 378-9983
Biography & Philosophy of Care
Dr. Ali Khalessi is a highly rated, double board-certified gastroenterologist and attending physician at Manhattan Gastroenterology, and a member of the faculty at the world-renowned NewYork-Presbyterian/Weill Cornell Medical Center. Trained at NYU Grossman School of Medicine and NYU Langone Medical Center, he combines the rigor of academic medicine with a warm, unhurried approach to patient care. During his gastroenterology fellowship at Rutgers New Jersey Medical School, he was selected to serve as Chief Fellow, a role reserved for physicians who show exceptional clinical judgment and leadership.
A highly skilled endoscopist, Dr. Khalessi performs screening and diagnostic colonoscopy, upper endoscopy, esophageal dilation, and hemorrhoid treatment. He has a special interest in inflammatory bowel disease and has cared for a large panel of patients with Crohn’s disease and ulcerative colitis on advanced biologic therapies. He also treats GERD, Barrett’s esophagus, fatty liver disease, IBS, and other digestive conditions, and offers comprehensive colon cancer screening.
His research spans inflammatory bowel disease, liver disease, esophageal disorders, and young-onset colorectal cancer. His work has appeared in the Journal of Clinical Gastroenterology, Clinics in Liver Disease, Gastro Hep Advances, and Gastroenterology, and he has presented at national meetings of the American College of Gastroenterology and the American Gastroenterological Association.
Dr. Khalessi believes great care starts with listening. He takes the time to explain each diagnosis and treatment option clearly and partners with his patients to build a plan that fits their lives. His expertise, compassion, and dedication have earned him an excellent reputation among patients and colleagues in New York City. Dr. Khalessi looks forward to meeting you.
Hospital Affiliations
- Weill Cornell Medical Center / NewYork-Presbyterian Hospital
Board Certifications
- Internal Medicine, American Board of Internal Medicine
- Gastroenterology, American Board of Internal Medicine
Education and Training
- Fellowship: Gastroenterology, Rutgers New Jersey Medical School (Chief Fellow)
- Residency: Internal Medicine, NYU Langone Medical Center
- Medical School: NYU Grossman School of Medicine, Doctor of Medicine
- Undergraduate: University of California, Irvine, B.S. in Biomedical Engineering, cum laude
Professional Memberships
- American College of Gastroenterology
- American Gastroenterological Association
- American Society for Gastrointestinal Endoscopy
Awards and Honors
- Chief Gastroenterology Fellow, Rutgers New Jersey Medical School
- Cum Laude Honors, University of California, Irvine
- SURP Research Award
Conditions Treated
- Crohn's disease and ulcerative colitis
- Colon polyps and colon cancer screening
- GERD, heartburn, and Barrett's esophagus
- Difficulty swallowing
- Hemorrhoids and rectal bleeding
- Constipation, fecal incontinence, and pelvic floor disorders
- Irritable bowel syndrome (IBS)
- Abdominal pain and bloating
Medical Publications
- “Differential Manifestations of Inflammatory Bowel Disease Based on Race and Immigration Status,” Gastro Hep Advances (in press)
- “Pharmacologic Management of Hepatic Encephalopathy,” Clinics in Liver Disease (in press)
- “Esophageal Function Abnormalities in Patients With Barrett’s Esophagus,” Journal of Clinical Gastroenterology, 2020
- “Trends and Complication Rates in Ulcerative Colitis Patients With and Without Helicobacter pylori Infections,” Cureus, 2023
- “Exploring The Cancer Genome Atlas (TCGA) for the Molecular Profile of Young-Onset Colorectal Cancers,” Gastroenterology (Digestive Disease Week abstract), 2020
- “A Rare Case of BRAF/MEK Inhibitor-Induced Colitis,” American Journal of Gastroenterology (ACG abstract), 2022
- “Primary Intestinal Lymphangiectasia Presenting as Refractory Edema in a Young Woman,” American Journal of Gastroenterology (ACG abstract), 2020
Provider Information
- Specialty: Internal Medicine – Gastroenterology (207RG0100X)