Internal Medicine Doctors in California
Data updated monthly · Last refresh October 2026
17,715 Internal Medicine providers practice in California, including 4,245 (24%) offering telehealth. The largest concentration is in Los Angeles. Profiles include federal Open Payments records of money received from drug and device companies in 2025. Listings are drawn from federal public records and are not endorsements.
17,715providers
4,245telehealth
Los Angelestop city
Internal Medicine by city in California
Choose a city to see providers there.
Where Internal Medicine Doctors in California practice
From CMS Medicare enrollment records covering 10,847 of the 17,715 providers listed here (61%). Providers who do not bill Medicare are not included in these figures.
20%solo or small practice (under 10 clinicians)
12%mid-size group (10 to 99)
67%large group or health system (100+)
Largest practice groups
| Group (as registered with Medicare) | Internal Medicine Doctors | All clinicians in group | Main city |
| Southern California Permanente Medical Group | 1,236 | 11,250 | San Diego |
| Permanente Medical Group Inc. | 1,203 | 10,928 | Richmond |
| Sutter Bay Medical Foundation | 396 | 3,783 | Palo Alto |
| The Regents of the University of California | 311 | 1,426 | Santa Monica |
| Stanford Health Care | 231 | 3,152 | Stanford |
Hospitals where they hold privileges
| Hospital | City | Ownership | CMS star rating | Internal Medicine Doctors affiliated |
| Stanford Health Care | Stanford | Nonprofit | 5 of 5 | 442 |
| UCSF Medical Center | San Francisco | Nonprofit | 4 of 5 | 326 |
| Ronald Reagan UCLA Medical Center | Los Angeles | Government | 4 of 5 | 308 |
| Cedars-Sinai Medical Center | Los Angeles | Nonprofit | 5 of 5 | 264 |
| Hoag Memorial Hospital Presbyterian | Newport Beach | Nonprofit | 5 of 5 | 246 |
Sources: CMS Doctors and Clinicians (August 2026) and Facility Affiliation files (August 2026); hospital ownership type and overall star rating from CMS Hospital General Information (July 2026). A clinician in several groups is counted once, in the largest group they bill through. Ownership type is what the hospital reports to CMS; it does not show private equity or other investor ownership. How we build this directory.
Internal Medicine providers in California
Listed by city, largest first. Payment figures come from the federal Open Payments program, which requires drug and device companies to report what they pay physicians for consulting, speaking, meals, travel and royalties. A disclosed payment is a financial relationship, not evidence of wrongdoing, and many totals reflect a single meal. Figures cover calendar year 2025.
Dr. Adrian Hill444 S Patterson Ste 200, CA · No drug or device payments recorded (2025) ·
(805) 681-6424 Dr. David Moskowitz, MDAgoura Hills, CA · No drug or device payments recorded (2025) ·
(818) 706-2477 Dr. Dilip Anmangandla, MD.Agoura Hills, CA · No drug or device payments recorded (2025) ·
(818) 483-6334 Dr. Jack Gindi, M.D.Agoura Hills, CA · No drug or device payments recorded (2025) ·
(818) 706-7773 Dr. Maria Jan, MDAgoura Hills, CA · $25 in drug and device payments (2025) · Telehealth ·
(818) 706-2477 Dr. Angela Chan, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 749-5731 Dr. Catherine PyunAlameda, CA · No drug or device payments recorded (2025) ·
(510) 514-4397 Dr. Charlie Chu, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 749-5731 Dr. Charmaine Shen, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 752-1000 Dr. Cheryl Scott, MD, MPHAlameda, CA · No drug or device payments recorded (2025) ·
(510) 437-3598 Dr. Christian SimeonAlameda, CA · No drug or device payments recorded (2025) ·
(510) 522-3700 Dr. Chuong Do, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 752-1000 Dr. David Belk, M.D.Alameda, CA · No drug or device payments recorded (2025) ·
(510) 769-7078 Dr. David Craney, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 749-5731 Dr. Dina Rosen, M.D.Alameda, CA · No drug or device payments recorded (2025) ·
(510) 814-4397 Dr. Elpidio Magalong, M.D.Alameda, CA · $394 in drug and device payments (2025) ·
(510) 227-5540 Dr. Ernest Bonner, MDAlameda, CA · No drug or device payments recorded (2025) ·
(810) 864-9600 Dr. Garland Castaneda, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 814-4397 Dr. Jacques Calma, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 522-6053 Dr. Jagmohan Khaira, M.D.Alameda, CA · $315 in drug and device payments (2025) · Telehealth ·
(510) 227-5540 Dr. James Kong, M.D.Alameda, CA · $3,371 in drug and device payments (2025) ·
(510) 769-1118 Dr. James Yeh, D.O.Alameda, CA · No drug or device payments recorded (2025) ·
(510) 814-4397 Dr. Jenna Brimmer, M.D.Alameda, CA · $815 in drug and device payments (2025) ·
(530) 814-4630 Dr. Joanne Dephillips, M.D.Alameda, CA · No drug or device payments recorded (2025) ·
(510) 814-4397 Dr. Kinjal PatelAlameda, CA · No drug or device payments recorded (2025) · Telehealth ·
(510) 323-4410 Dr. Lorraine Bonner, M.D.Alameda, CA · No drug or device payments recorded (2025) ·
(510) 814-4397 Dr. Loton Shippey, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 814-4397 Dr. Luke Lin, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 814-4391 Dr. Mark Marrama, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 749-5731 Dr. Mary Herner, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 752-1000 Dr. Quynh Nguyen, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 749-5731 Dr. Ray Yeh, D.O.Alameda, CA · No drug or device payments recorded (2025) ·
(510) 814-4397 Dr. Robbin Green-yeh, DOAlameda, CA · No drug or device payments recorded (2025) ·
(510) 814-4630 Dr. Samra Rashid, D.O.Alameda, CA · No drug or device payments recorded (2025) ·
(510) 814-9397 Dr. Sunil Desai, MDAlameda, CA · No drug or device payments recorded (2025) ·
(808) 243-6050 Dr. Tigist Tekle Siacha, MDAlameda, CA · No drug or device payments recorded (2025) ·
(510) 752-1190 Dr. Donald Nielsen, MDAlamo, CA · No drug or device payments recorded (2025) ·
(925) 933-4710 Dr. Edward Shin, M.D.Alamo, CA · No drug or device payments recorded (2025) ·
(646) 418-3015 Dr. Howard Zeiger, M.D.Alamo, CA · $18 in drug and device payments (2025) · Telehealth ·
(925) 837-4225 Dr. James Woods, M.D.Alamo, CA · No drug or device payments recorded (2025) ·
(925) 837-4225 Dr. Janet Gaston, M.D.Alamo, CA · No drug or device payments recorded (2025) ·
(925) 837-4225 Dr. Leonard Chuck, MDAlamo, CA · No drug or device payments recorded (2025) ·
(925) 952-2888 Dr. Manisha Malhotra, M.D.Alamo, CA · $603 in drug and device payments (2025) · Telehealth ·
(925) 838-5750 Dr. Nhu Pham, M.D.Alamo, CA · No drug or device payments recorded (2025) ·
(925) 838-5750 Dr. Amal Sawires, M.D.Albany, CA · No drug or device payments recorded (2025) ·
(510) 204-8130 Dr. Anderson Tsai, D.O.Albany, CA · No drug or device payments recorded (2025) ·
(510) 204-8130 Dr. Ira Fishman, M.D.Albany, CA · No drug or device payments recorded (2025) ·
(510) 524-1680 Dr. Jeffrey Karon, MDAlbany, CA · No drug or device payments recorded (2025) · Telehealth ·
(510) 204-8130 Dr. Maya Pandurangi, D.OAlbany, CA · No drug or device payments recorded (2025) · Telehealth ·
(510) 204-8130 Conditions Internal Medicine providers in California commonly treat
Patients often search by condition rather than specialty. These are conditions typically managed by Internal Medicine providers. Individual practices vary, so confirm with the provider before booking.
- High blood pressure
- Type 2 diabetes
- High cholesterol
- Preventive care
- Chronic disease management
Common questions
How many Internal Medicine providers are in California?There are 17,715 Internal Medicine providers with active NPI records practicing in California, according to federal NPPES data refreshed monthly.
Do Internal Medicine providers in California offer telehealth?Yes. 4,245 of the 17,715 Internal Medicine providers in California (about 24%) report offering telehealth services in CMS data.
Which cities in California have the most Internal Medicine providers?Los Angeles (1,417), San Francisco (1,322), San Diego (970) have the highest concentration of Internal Medicine providers in California.
How many Internal Medicine providers in California received drug or device company payments?5,614 of 17,715 Internal Medicine providers in California (32%) received at least one payment from a drug or device company in 2025, according to the federal Open Payments program.
What conditions do Internal Medicine providers in California treat?Internal Medicine providers commonly treat high blood pressure, type 2 diabetes, high cholesterol, preventive care, chronic disease management and related conditions. Individual practices vary, so confirm with the provider before booking.
Where does this data come from?Provider counts and profiles come from the federal NPPES registry and CMS Doctors and Clinicians files. Payment figures come from the CMS Open Payments program for calendar year 2025. The directory refreshes monthly.
Do most Internal Medicine Doctors in California work in independent practices or large health systems?Among 10,847 Internal Medicine Doctors in California enrolled in Medicare, 20% bill through a solo or small practice with fewer than 10 clinicians, 12% through a mid-size group of 10 to 99, and 67% through a large group or health system with 100 or more clinicians, according to CMS enrollment records.
Which hospitals do Internal Medicine Doctors in California work at?According to CMS facility affiliation records, the California hospitals where the most Internal Medicine Doctors hold privileges are Stanford Health Care in Stanford; UCSF Medical Center in San Francisco; Ronald Reagan UCLA Medical Center in Los Angeles.
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