Pictured: Margaret Callahan

Margaret K. Callahan, MD, PhD

Medical Oncologist


Research Director, Immunotherapeutics Program

Clinical Expertise

Melanoma; Immunotherapy

New Patient Appointments

Scheduling a visit is easy. Click below or call us to get started.

Accepted Insurance Providers

Dr. Callahan accepts the following list of insurance providers. Select your insurance provider to see more details.

Contact and Location

Locations map

Find a Convenient Location

Memorial Sloan Kettering has locations throughout New York City, Long Island, New Jersey, and Westchester. These locations offers many services, including screening, chemotherapy, and medical testing.

About Me


MD, PhD, University of Connecticut School of Medicine


University of California, San Francisco, Medical Center


Memorial Sloan Kettering Cancer Center

Board Certifications

Internal Medicine; Medical Oncology

I am a board-certified medical oncologist who specializes in the use of novel immunotherapies, which act by stimulating or strengthening the immune system’s inherent ability to fight cancer, to treat melanoma and other cancers. I work closely with a multidisciplinary team of medical oncologists, surgeons, radiation oncologists, and research nurses in the Immunotherapeutics Clinical Core (a specialized center for phase I clinical trials of new immunotherapy agents) and on the Melanoma and Sarcoma Service.

My research is focused on the development of new ways to use the immune system to treat cancer. As a laboratory member in the Ludwig Center for Cancer Immunotherapy at Memorial Sloan Kettering, I have been involved in developing innovative approaches to monitoring patients treated with immunotherapy. Our hope is to better understand how immunotherapy can be used to help patients with cancer and to expand this promising treatment modality into new areas.


Doctors at Memorial Sloan Kettering work as teams, with specialists from all different areas. This allows us to consider all your needs together, and to give you the best possible care.

Clinical Trials

Smiling doctors in the lab

Find a Clinical Trial for You

Memorial Sloan Kettering's doctors and scientists are constantly developing new treatments for cancer. MSK is typically running hundreds of clinical trials at a given time.

You may be able to participate in a clinical trial even if you are new to MSK. Search our online directory to find trial information and see more about who can participate.

Research and Publications

View Dr. Callahan's Lab

Publications on PubMed

Visit PubMed for a full listing of Dr. Callahan’s journal articles. Pubmed is an online index of research papers and other articles from the US National Library of Medicine and the National Institutes of Health.