Blue Shield got its start in 1938 when the California Medical Association House of Delegates created California Physicians’ Service (CPS). By 1940 over 20,000 Californians had subscribed and 5,000 physicians had joined the healthcare service plan.
Blue Shield became one of the founders of the National Association of Blue Shield Plans in 1946, which was later renamed the Blue Cross and Blue Shield Association.
In 1961, Blue Shield hit 1,000,000 subscribers. They entered the health maintenance organization business by establishing Blue Shield HMO in Sacramento in 1988 and in 1989 Blue Shield entered its 50th year of business. It now serves nearly three million Californians with a provider network of over 36,000 Physician Members and nearly 240 Preferred Hospitals.
Blue Shield entered Medi-Cal and Medicaid with the acquisition of Care1st Health Plan in 2015.