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.
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. Eric Kopf, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 927-5136 Dr. Eric Lee, M.D.Napa, CA · No drug or device payments recorded (2025) ·
(707) 252-4411 Dr. Ernest Arras, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 258-2500 Dr. George Vellucci, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 258-2500 Dr. Grace Ang, M.D.Napa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. Herbert Bazron, MDNapa, CA · $131 in drug and device payments (2025) · Telehealth ·
(707) 703-4863 Dr. Hong-shen Yeh, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. Jahed Kamal, M.D.Napa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. Jan Krupp, M.D.Napa, CA · No drug or device payments recorded (2025) ·
(707) 259-1198 Dr. Jaskaran Momi, M.D.Napa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. John Rupnik, M.D.Napa, CA · No drug or device payments recorded (2025) ·
(707) 253-8901 Dr. Julie Winter, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 258-2500 Dr. Kelvin Mar-tang, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 258-2500 Dr. Lane Melgarejo, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. Larry Bryson, M.D.Napa, CA · No drug or device payments recorded (2025) ·
(415) 990-0083 Dr. Macaria VillalobosNapa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. Manuel Ballesca, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 258-2500 Dr. Maria Tabilon, MDNapa, CA · No drug or device payments recorded (2025) · Telehealth ·
(707) 258-2500 Dr. Mark Singer, M.D.Napa, CA · No drug or device payments recorded (2025) ·
(707) 365-5151 Dr. Marlene Salvador, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. Marshall Cooperson, DONapa, CA · No drug or device payments recorded (2025) ·
(707) 257-1550 Dr. Marvin Sakakihara, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 258-2500 Dr. Mary Rose Huber, M.D.Napa, CA · No drug or device payments recorded (2025) ·
(707) 252-4872 Dr. Michael Harrington, MD Dr. Michele Wilson, MDNapa, CA · No drug or device payments recorded (2025) · Telehealth ·
(707) 258-2500 Dr. Mu Chou, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. Patricia Dizmang, M.D.Napa, CA · No drug or device payments recorded (2025) ·
(707) 253-7861 Dr. Paul Sweigert, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 927-5322 Dr. Peter Mathews, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 258-2500 Dr. Phu Truong, MDNapa, CA · No drug or device payments recorded (2025) · Telehealth ·
(707) 258-2500 Dr. Raissa Paredes, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. Robert Hopkins, MD, MPH & TMNapa, CA · No drug or device payments recorded (2025) ·
(707) 254-1775 Dr. Rodolfo Pineda, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. Rony Kako, MDNapa, CA · $41 in drug and device payments (2025) · Telehealth ·
(707) 257-1550 Dr. Roxana Mundy, MDNapa, CA · No drug or device payments recorded (2025) · Telehealth ·
(707) 258-2500 Dr. Ruth Wilson, M.D.Napa, CA · No drug or device payments recorded (2025) · Telehealth ·
(707) 255-3583 Dr. Scott Anderson, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. Sukhbir Singh, D.O.Napa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. Wai-shing Ng, M.D.Napa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. William Kocsis, MDNapa, CA · No drug or device payments recorded (2025) ·
(707) 253-5000 Dr. Andrew Alongi, M.D.National City, CA · No drug or device payments recorded (2025) ·
(619) 779-7905 Dr. Archie Bella, M.D.National City, CA · $756 in drug and device payments (2025) ·
(844) 200-2426 Dr. Arwinnah Bautista, MDNational City, CA · $4,010 in drug and device payments (2025) · Telehealth ·
(619) 434-2813 Dr. Aurore Oughourlian, M.D.National City, CA · No drug or device payments recorded (2025) ·
(619) 662-4100 Dr. Brenda Watts, M.D.National City, CA · No drug or device payments recorded (2025) · Telehealth ·
(619) 515-2399 Dr. Griselda Tiu, MDNational City, CA · $526 in drug and device payments (2025) ·
(619) 475-4004 Dr. Irineo Tiangco, M.D.National City, CA · $2,153 in drug and device payments (2025) · Telehealth ·
(619) 479-0320 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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