Xavier Llor, MD,PhD


Gastroenterology, Internal Medicine

Conditions & Treatments

Cancer Genetics, Colon Cancer, Colorectal Cancer, Digestive Diseases, Gastrointestinal Cancer

(203) 785-4138
Accepting New Patients
Telehealth Visits


Xavier Llor, MD, PhD, is a gastroenterologist at Yale Medicine with a specialty in gastrointestinal cancer genetics and colorectal cancer. He is the co-director of the Smilow Cancer Genetics and Prevention Program, associate director for cancer screening at the Center for Community Engagement and Health Equity at Yale Cancer Center, and the medical director of the Colorectal Cancer Prevention Program. 

After receiving a medical school education from the Autonomous University in Barcelona, Dr. Llor trained in basic research and internal medicine at the University of Chicago and completed his PhD in molecular biology from the University of Barcelona. Dr. Llor completed his GI fellowship at the University of Illinois at Chicago. His background as both a clinician and researcher led him to specialize in cancer genetics, where he works to identify specific genes that make a person more susceptible to gastrointestinal cancers. “One of the most rewarding things about this field is that every day we seem to discover more, and that knowledge is translated very quickly into patients’ lives,” says Dr. Llor.

As a physician, Dr. Llor uses his research to better care for his patients. The goal is to identify cancer risk as early as possible. This knowledge can help patients take measures to prevent cancer, or it can help doctors treat patients with cancer as early as possible. “The earlier a cancer is detected, the better the prognosis is,” says Dr. Llor. 

In addition, genetic defects that are linked to gastrointestinal cancers may also be linked to cancers in other parts of the body. “We take a broad and comprehensive approach to patients in making sure that we prevent all cancers that are linked to those particular genetic defects,” says Dr. Llor.

As a researcher, Dr. Llor continues to identify new genetic defects that may be linked to colorectal and other GI cancer risk. Furthermore, he is exploring different approaches that lead to a wider identification of these diseases, with a particular emphasis in disseminating this specialized care among the underserved. He has made important contributions to the field of Lynch syndrome (a hereditary form of colorectal cancer). 

Dr. Llor is a professor of medicine (digestive diseases) at Yale School of Medicine.





Years In Practice


Affiliated With

Smilow Cancer Hospital, Yale Medicine


Yale Digestive Diseases

40 Temple Street
Suite 1A
New Haven, CT 06510

Get Directions

Monday9:00 AM - 5:00 PM
Tuesday9:00 AM - 5:00 PM
Wednesday9:00 AM - 5:00 PM
Thursday9:00 AM - 5:00 PM
Friday9:00 AM - 5:00 PM
(203) 737-1345

Yale New Haven Hospital

20 York Street
New Haven, CT 06510

Get Directions

Monday9:00 AM - 5:00 PM
Tuesday9:00 AM - 5:00 PM
Wednesday9:00 AM - 5:00 PM
Thursday9:00 AM - 5:00 PM
Friday9:00 AM - 5:00 PM
(203) 200-2235

Education & Training


University of Barcelona


University of Chicago


Lutheran General (Internal Medicine)


University of Illinois

Accepted Insurance

Insurance coverage regularly changes, please contact the doctor’s office directly to verify that your specific insurance plan is accepted.

  • aetna
  • anthem bc/bs
  • berkeley care network
  • cigna healthcare
  • community care network
  • connecticare
  • corvel
  • first health network
  • focus healthcare
  • great west
  • husky
  • medicaid
  • medicare
  • multiplan
  • oxford health plans
  • railroad medicare
  • tricare/champus
  • united healthcare
  • us family health plan
  • wellcare