Marlon DeCastro, MD

4.8 out of 5 (112 Ratings)
  • Internal Medicine
Additional Language Spoken
Internal Medicine – Doyle Park Suite 303
500 Doyle Park Dr.
Suite 303
Santa Rosa, CA 95405

Primary Office

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

More Information

Medical Groups & Affiliations
  • St. Joseph Health Medical Group
  • Meet The Doctor

    Specialties & Education

    Primary Specialties
    • Internal Medicine
    Education & Training
    • Medical School
      University of the Philippines- Manila, Philippines
    • Internship
      Nassau Univ Medical Center- East Meadow, NY
    • Residency
      Nassau Univ. Medical Center- East Meadow, NY
    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.
  • 21-Aug-2018
    Dr DeCastro is excellent.
    Very easy to talk w/the doctor & entire office staff!
    Shows concerns about my health problem.
    *Dr. DeCastro is amazing. I don't think I would be alive and functioning if it wasn't for him.
    Laughs upon seeing client, makes client feel uncomfortable and wrong for symptoms. It's difficult to share information with provider because of this.
    8 Total Comments Page 1 2   Next