United Medical Doctors Discloses Data Breach Affecting Patients

United Medical Doctors, a large independent multi-specialty medical and surgical group headquartered in Murrieta, California, disclosed a data breach that may have exposed personal information belonging to certain current and former patients.

An investigation found that an unauthorized user had gained access to the company's computer systems at varying times between Dec. 12, 2025, and March 31, 2026. During the period, the unauthorized user may have viewed or acquired certain files stored within the company's digital environment.

As of the notification date of May 20, 2026, the specific types of information involved in the breach remain undisclosed. United Medical Doctors stated it is actively reviewing the affected files to understand whether any sensitive personal, financial or medical information related to individuals may be contained in them.

United Medical Doctors began notifying consumers on May 20, 2026. The company posted a notice of the data event on its website and disclosed the incident to the U.S. Department of Health and Human Services.

The total number of individuals affected has not been publicly disclosed.

United Medical Doctors' response

The company encouraged affected individuals to remain vigilant by reviewing account statements and monitoring credit reports for suspicious activity and provided guidance on how to protect their information.

Affected individuals can reach Equifax at 1-888-298-0045, Experian at 1-888-397-3742 and TransUnion at 1-833-799-5355. The company's notification explained that consumers have the right under federal law to place fraud alerts or credit freezes on their credit files at no charge.

The company also directed individuals to the Federal Trade Commission for additional identity theft resources, noting that the FTC can be reached at www.identitytheft.gov, by phone at 1-877-438-4338, or by mail at 600 Pennsylvania Ave. NW, Washington, D.C. 20580.