Marlon DeCastro, MD

4.7 out of 5 (120 Ratings)
  • Internal Medicine
Additional Language Spoken
Tagalog, English
Medical Groups & Affiliations
  • St. Joseph Health Medical Group
  • St. Joseph Health Medical Network
St. Joseph Health Santa Rosa - Doyle Park Internal Medicine Suite 303
500 Doyle Park Drive
Suite 303
Santa Rosa, CA 95405

Primary Office

St. Joseph Health Santa Rosa - Doyle Park Internal Medicine Suite 303
500 Doyle Park Drive
Suite 303
Santa Rosa, CA 95405
Get Directions
(707) 303-8300
(707) 303-8301

More Information

  • Meet The Doctor

    Specialties & Education

    Primary Specialties
    • Internal Medicine
    Education & Training
    • Medical School
      University of the Philippines
    • Internship
      Nassau Univ Medical Center- East Meadow
    • Residency
      Nassau Univ. Medical Center- East Meadow
    Areas of Interest
    Family Medicine, General Practice, Internal Medicine
  • Biography


    As an internist, Dr. DeCastro specializes in providing patient-centered care for adults of all ages. He is board certified in Internal Medicine and able to care for an individual's specific medical needs from preventive services to the diagnosis, treatment and management of acute and chronic conditions and diseases. He is especially adept at treating individuals with diabetes.

    Dr. DeCastro received his medical degree from the University of the Philippines in Manila, and conducted an Internal Medicine residency at Nassau University Medical Center in East Meadow, New York. Most recently, Dr. DeCastro served as an attending physician at Clemson Health Center in South Carolina where he provided primary care to adults and served as lead investigator in several studies. While there, he also earned certification in the Diabetes Physician Recognition Program, presented by the National Committee for Quality Assurance.
  • 30-Jan-2020
    Good. Very comfortable with them and love how friendly they are.
    This was a new patient visit so the provider was just meeting me for the first time and didn't have any of my records yet. He was nice, professional and busy it seemed (not in a bad way).
    Very satisfied - All my medical needs met -
    Very thorough & professional
    dr. Did everything. That I had on my list. I had emailed him my concerns. When I got there he knew what we were going to talk about. And we proceeded. I had it in a couple other items. That we will take care of in a Nother visit. The lab work was on site so I could go do it. Easily and the x-rays were on site at the same spot. The way I had to come back the next day for the lab work. It was a fasting. My doctor is knowledgeable. And I appreciate his help. I started with him last year once and this is my second visit I got very busy last year. I will try to keep regular visits with him
    55 Total Comments Page 1 2 3 4 5 6 7 8 9 10 11   Next