Careers With St. Joseph Health

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They form the heart and soul of St. Joseph Health and are the prime reason we attract and retain high-caliber employees who believe in the sanctity of their work in our faith-based setting.

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About St. Joseph Health

SJH provides a full range of care facilities including 16 acute care hospitals, home health agencies, hospice care, outpatient services, skilled nursing facilities, community clinics and physician groups. All of our hospital and home health entities are accredited by the Joint Commission. In our award-winning facilities, SJH maintains a "continuum of care," matched to the diverse needs of the urban centers, smaller cities and rural communities who depend on us every day.

Maruja Diaz-Arjonilla, MD

4.7 out of 5 (78 Ratings)
  • Endocrinology, Diabetes & Metabolism
    (Board Certified)
Additional Language Spoken
Medical Groups & Affiliations
  • St. Joseph Heritage Medical Group
St. Joseph Heritage Medical Group
2212 E. 4th St.
Suite 304
Santa Ana, CA 92705
Accepting New Patients
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Primary Office

St. Joseph Heritage Medical Group
2212 E. 4th St.
Suite 304
Santa Ana, CA 92705
Get Directions
(714) 288-3230
(714) 571-7719
M, Tu, Wed, Fri: 8 a.m. - 5 p.m. Thu: 8 a.m. - 12 p.m.

More Information



  • Meet The Doctor

    Specialties & Education

    Primary Specialties
    • Endocrinology, Diabetes & Metabolism
      (Board Certified)
    Secondary Specialties
    • Internal Medicine
      (Board Certified)
    Education & Training
    • Medical School
      Universidad Central de Venezuela, Caracas, Venezuela - 1990
    • Internship
      Universidad Central de Venezuela, Caracas, Venezuela - 1992
    • Residency
      UCSF - Fresno- Fresno, CA - 2007
    • Fellowship
      Harbor, UCLA Medical Center- Los Angeles, CA - 2009
  • Biography


    As an endocrinologist, I care for many conditions including: diabetes, thyroid disease, calcium and metabolism disorders and adrenal and pituitary gland conditions. I practice patient-centered care, emphasizing in two-way communication and patient and family education.
  • 30-Dec-2018
    Dr Diaz shows great care for me, really takes the time to explain test results , recommendations and takes considerable care to research my Heath concerns and find the best treatments and providers to address my Health issues.
    *Doc Diaz, listens very well to all I have to ask my questions. She is a wonderful person.
    My first visit w/*Dr. Diaz and I was very happy w/her. I feel she really understood my problems w/my thyroid.
    They are all very kind, respectful and friendly.
    Dr. Diaz is an exceptional doctor! Dr. Diaz has a very calming demeanor & is certainly very interested in the well being of her patients. I am very blessed to have her as my endocrinologist!
    10 Total Comments Page 1 2   Next
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