Leonard Farber

Leonard A. Farber, M.D.

  • Assistant Clinical Professor, Department of Radiation Oncology
  • Radiation Oncologist

Leonard A. Farber, M.D.

Clinical Specialties
  • Radiation Oncology
Areas of Expertise
  • Breast cancer
  • Prostate cancer
  • Lymphoma
  • Head and neck cancer
  • Lung cancer
At a very young age Leonard Farber, M.D., watched his grandfather battle cancer. “When he passed away,” he recalls, “I vowed that I would dedicate myself to treating cancer and seeing that patients would be treated better than how he spent the last months of his life.”

For more than two decades now, Dr. Farber has followed that promise, providing care at prestigious facilities across the New York area, as well as building and operating his own state-of-the-art radiation oncology center. Along the way, he's earned stellar reviews from patients and over a dozen “Super Doctor” and “Top Doctor” honors.

Dr. Farber received his medical degree at Mount Sinai School of Medicine in New York City. He continued his training with an internship at Beth Israel Medical center and residency at the Hospital of the University of Pennsylvania, Philadelphia.
  • 2018 - present, Assistant Clinical Professor, Department of Radiation Oncology, City of Hope, Duarte, CA
  • 2014 - 2017, Clinical Director, Radiation Oncology and Assistant Professor, Clinical Radiation Oncology, New York-Presbyterian/Lower Manhattan Cancer Center, Weill Cornell Medicine, New York, NY
  • 2017, Radiation Oncologist, Professor, Memorial Sloan Kettering Cancer Center, New York, NY
  • 2010 - 2014, Founder and Clinical Director, The Farber Center for Radiation Oncology, New York, NY
  • 2010 - 2013, Attending Radiation Oncologist, New York Downtown Hospital, New York-Presbyterian Healthcare System, New York, NY
  • 2008 - 2009, Chair, Department of Radiation Oncology, Staten Island University Hospital, Staten Island, New York
  • 2007 - 2008, Clinical Director of Radiation Oncology, Long Island Radiation Therapy/Nassau Radiologic Group, PC Long Island, New York

2151 N. Harbor Blvd., Suite 1500
Fullerton, CA  92835


  • 1994, M.D., Mount Sinai School of Medicine, New York, NY
  • 1990, B.S. Biology, B.A. Philosophy, State University of New York, Binghampton, NY


  • 1997 - 1998 Chief Resident, Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, PA
  • 1995 - 1997 Resident, Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, PA


  • 1994 - 1995 Intern, Internal Medicine, Beth Israel Medical Center, New York, NY
  • 2012 - 2017 Super Doctors
  • 2012, 2014 Top Doctors Award in Radiation Oncology
  • 2011 - 2012 Best Doctors
  • 2009 - 2011 America's Top Oncologists Award in Radiation Oncology
  • 2004 - 2005 America's Top Physicians Award in Radiation Oncology
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