Dr. Rena D. Callahan, M.D.

Female Internal Medicine, Hematology more...

(1 review)
Accepting new patients 15 years of experience Offers telehealth


Dr. Rena D. Callahan, M.D. is an Internist (Primary Care Doctor) in Valencia, CA. She specializes in Internal Medicine, Hematology, Medical Oncology, and Surgical Oncology, has 15 years of experience, and is board certified. She graduated from University of California At Los Angeles and she is affiliated with UCLA Santa Monica Medical Center, Ronald Reagan UCLA Medical Center, and Henry Mayo Newhall Hospital.

Dr. Callahan works at Limited To Official Government Duties On and 2 other...



Primary Location

Uc Regents Ucla Dmpg Santa Clarita

23929 McBean Pkwy Ste 215,

Valencia, CA 91355

Limited To Official Government Duties On

2020 Santa Monica Blvd Ste 580,

Santa Monica, CA 90404


Ucla 100 Mp # 550,

Los Angeles, CA 90095

Admitting Hospitals

  • Henry Mayo Newhall Hospital
  • Ronald Reagan UCLA Medical Center
  • UCLA Santa Monica Medical Center

Find providers based on your care needs

User Ratings (of at least 4.0)

Accepting New Patients

Insurance Accepted

Conditions Treated and Procedures Performed

Headshot Available

Start the search for a new doctor with Super Profiles and customizable filters that matter the most to you.

Experience & Treatment Frequency

Search for conditions or procedures.

Breast Cancer
Deep Vein Thrombosis (DVT)
Anal and Rectal Cancer
Breast Cancer
Close Icon

Treatment Frequency

Very High
Learn more about Breast Cancer View other providers who treat this condition
Deep Vein Thrombosis (DVT)
Close Icon

Treatment Frequency

View other providers who treat this condition
Anal and Rectal Cancer
Close Icon

Treatment Frequency

View other providers who treat this condition

Conditions and Procedures FAQ

What is treatment frequency? And why is it so important?
Why doesn’t a provider cover a condition or procedure in their specialty?
Why doesn’t my insurance provider cover a condition or procedure?

Check your insurance

Insurance FAQ

We know health insurance can be a tricky topic. So, we’ve broken down the most important aspects of health insurance by defining key terms and answering commonly asked questions.

How can your health insurance company help you?
What does in-network mean?
Why doesn’t a provider accept my insurance?

Ratings & Reviews

Average provider rating


Based on 1 review

Provider Rating

Time with patient

Listening skills

Clear explanations

Trust in decision making

Office & Staff Evaluation

Office appearance

Ease of scheduling

Friendly staff

Average wait time

Leave a review

How was your appointment with Dr. Rena D. Callahan, M.D.?

Patient Ratings (21)
5 star
4 star
3 star
2 star
1 star
Patient Reviews (1)
Mar 27, 2022

I credit Dr. Callahan with saving my life. I had visited other oncologists and was confused, scared and hopeless. She was an inspiration. I have already beaten all of the statistics that I was given a few years ago. Dr. Callahan is a wonderful...


About Dr. Rena D. Callahan, M.D.


  • Internal Medicine
  • Hematology
  • Medical Oncology
  • Surgical Oncology

Years of Experience

15 years of experience

Languages Spoken

  • English

NPI Number


Education & Certifications

Medical Education

  • University Of Pennsylvania School Of Medicine


  • UCLA


  • University of California At Los Angeles

Board Certifications

  • Hematology
  • Medical Oncology
  • Oncology

Frequently Asked Questions

Is Dr. Rena D. Callahan, M.D. accepting new patients?

Dr. Callahan is accepting new patients on Healthline FindCare. You can check to see if Dr. Callahan is offering online scheduling or call the provider’s office for more information.

Who are other Internists (Primary Care Doctors) nearby?
Does Dr. Rena D. Callahan, M.D. accept my insurance?

Dr. Callahan accepts Aetna, Anthem, Blue Cross Blue Shield, Blue Cross Blue Shield of California, and other major insurance plans. Please call ahead to confirm all accepted insurance plans.

Are you Dr. Rena D. Callahan, M.D.?

Claim your profile through Healthgrades to keep it updated and reach more patients.

It’s free and only takes a minute.

Claim My profile

Emergency Banner

In the event of a medical emergency, dial 911 or visit your closest emergency room immediately.