Marlon DeCastro, MD

4.8 out of 5 (133 Ratings)
  • Internal Medicine
Tagalog, English
Internal Medicine – Doyle Park Suite 303
500 Doyle Park Drive
Suite 303
Santa Rosa, CA 95405

Primary Office

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

More Information

Medical Groups & Affiliations
  • St. Joseph Health Medical Group
  • St. Joseph Health Medical Network
  • 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.
  • 4-Jun-2019
    Felt very comfortable w Dr DeCastro. He listened to me and discussed his thoughts with me.
    no comment everything is good .
    feel at ease at all time. thanks for your concern.
    Dr. DeCastro always has my best interests in mind. There is a medication I need that is not covered by insurance. I told him it was too expensive at my usual pharmacy ($99). He suggested another pharmacy where the savings were over $82 (it cost about $16.99), and I received 120 more capsules for the price. I was impressed with his knowledge and for the great suggestion. I feel I can trust him, and that he is a top notch doctor.
    Very good experience was very happy to meet my new doctor and he was very nice and very thorough and he definitely cares about his patients and I'm looking forward to seeing him in the future thank you very much dr. Decastro
    43 Total Comments Page 1 2 3 4 5 6 7 8 9   Next