Mary O’Sullivan, DNP, ARNP

Mary O’Sullivan, DNP, ARNP

Mary O’Sullivan, DNP, ARNP

  • Advanced Registered Nurse Practitioner, Fred Hutch
  • Teaching Associate, Division of Hematology and Oncology, University of Washington School of Medicine


“I understand that people’s goals can change from one day to the next, and I will be here to help achieve them.”

— Mary

What do you like about working at Fred Hutch?

Fred Hutch is a world-renowned cancer research and treatment center. We are constantly pushing the envelope and improving cancer treatments and outcomes. We individualize our care and help patients achieve their goals. Cancer impacts every facet of life; we understand that, and we are here to guide and support our patients and their loved ones.

Do you have a favorite memory of working with patients you’d like to share?

As a bedside nurse, I would often care for patients undergoing inpatient chemotherapy. I always loved being able to join patients on their walking laps through hospital hallways. It felt like a time to socialize and really get to know people. One of the most frequent comments I received from patients was about how gentle I was. Now, as a nurse practitioner, I aim to use this tendency of mine to lead with empathy, compassion and respect.

Provider Background

Area of Clinical Practice
Blood and marrow transplant, immunotherapy

I am an advanced registered nurse practitioner who sees patients at the South Lake Union Clinic and Fred Hutch at UW Medical Center – Montlake.

Exciting advancements are regularly being made in cancer care, especially in immunotherapy and blood and marrow transplant. These individualized treatments are the way of the future for cancer treatment. My nursing passion has always been in cancer care, and working on a team that can offer the most advanced treatments makes my work even more special. 

Diseases Treated



Education, Experience and Certifications

Undergraduate Degree
University of Pittsburgh

Medical Degree
University of Washington

Board Certification
Adult-Gerontology Acute Care Nurse Practitioner, 2023, American Nurses Credentialing Center

Clinical Trials

We make promising new treatments available to you through studies called clinical trials led by Fred Hutch physicians. Many of these trials at Fred Hutch have led to FDA-approved treatments and have improved standards of care globally. Together, you and your physician can decide if a study is right for you.

Your Care Team

At Fred Hutch, you receive care from a team of providers with extensive experience in your disease. Your team includes physicians, a patient care coordinator, a registered nurse, an advanced practice provider and others, based on your needs. You also have access to experts like registered dietitians, social workers, acupuncturists, psychiatrists and more who specialize in supporting people with cancer or blood disorders.


Fred Hutch accepts most national private health insurance plans as well as Medicare. We also accept Medicaid for people from Washington, Alaska, Montana and Idaho. We are working to ensure that everyone, no matter what their financial situation, has access to the care they need.

For the Media

The Media Relations team at Fred Hutch is available to assist members of the news media who would like to arrange interviews with providers.

Email or call 206.667.2210