Jonathan S. Lown, MD

My Philosophy and Approach to Wellness...

As an Internist, I have developed a deep understanding of wellness and long-term healthcare. My approach focuses on helping patients live better and longer lives through both acute and preventive care. I give every patient personal advice and support in a relaxed and unrushed manner. I utilize the latest advancements in medicine and knowledge of the latest discoveries in medical research and wellness screenings to help identify risk for disease and prevent it or treat it early. It is also important to me to foster and promote optimism and good humor, which are also important elements in the healing process and staying well.

I focus on primary care, internal medicine, cardiovascular health, preventive medicine and women’s health. In addition, I am board certified in sleep medicine and am able to treat sleep-related illnesses, such as obstructive sleep apnea and insomnia while providing guidance on CPAP management. My patients also enjoy conveniences similar to services in a concierge practice - timely appointments, same-day visits and the ability to contact me during and after hours. By promoting physical and mental well-being and coaching healthier lifestyle choices, I empower my patients to live the best life possible.

My private primary care practice currently serves all of Long Island, New York. My office is conveniently located in Commack, which is easily accessible from Eastern Nassau County and Western Suffolk County. I am affiliated with St. Catherine of Siena Medical Center in Smithtown, New York. I speak fluent English and Spanish.

Physician Profile


State University of New York - Plattsburgh
Plattsburgh, NY
Bachelor of Science, Biology 1987
Medical School
State University of New York - Downstate
Downstate, NY
Doctorate of Medicine 1995
Magna Cum Laude
Columbia Presbyterian Medical Center
New York, NY
Columbia Presbyterian Medical Center
New York, NY


New York

Professional Society Memberships

American Academy of Sleep Medicine
American College of Physicians
American College of Chest Physicians
National Lipid Association
Suffolk County Medical Society

Professional Affiliations and Appointments

Professor/Clinical Preceptor, Stonybrook University Medical School 1995-present

Hospital Affiliations

St. Catherine of Siena

Honors and Awards

Alpha Omega Alpha, Medical Honor Society

Published Works

Sasak, V., Lown, J., Colburn, K., Human Small Intestinal Apolopoprotein B-48 Oligaosaccharide Chains, Biochemical Journal 1991
High-affinity NGF binding requires co-expression of the trk prto-oncogene and the low Affinity NFG receptor, Nature 1991 (Acknowledgment)




Diplomate in Internal Medicine, American Board of Internal Medicine 1998-present
Diplomate in Sleep Medicine, American Board of Internal Medicine 2009-present
Diplomate of Clinical Lipidology, American Board of Clinical Lipidology 2006-present

Patient Testimonials

  • Member: steve

    dr/.lown thanks for caring for me and my family on so many levels.brilliant doctor caring beyond words

  • Member: Frederick

    I have known Dr. Lown for many years and consider him a friend and my physician. Dr Lown goes out of his way to accommodate his pa...

  • Member: Phyllis

    When dr. Fagan retired I had to select another doctor , it was Dr. Lown. What a pleasant surprise!! He was and is an outstanding...

  • Member: Michael

    At 59 years old I believe Dr. Lown is the finest doctor that I have ever had. I have been a patient for 8 years before he became a...