Investigators said one of those patients was a 16-year-old girl. Dr. Yashwant Giri, 58, is an anesthesiologist at Placentia-Linda Hospital.
Employees said they witnessed Giri fondle a 16-year-old girl in 2009 and a 36-year-old woman in March 2011.
Both patients were reportedly unconscious on the operating table at the time.
Placentia-Linda Hospital issued the following statement:
In a statement, a hospital official said: "We take allegations such as this very seriously. The hospital and medical staff immediately launched an internal review. The physician resigned from our staff last month. We have reported the incidents to California Department of Public Health, the medical board and local authorities, and we are cooperating fully with their investigations."
Police said there may be other victims. Authorities say Giri worked at West Anaheim Medical Center, Anaheim Regional Medical Center, and Western Medical Center-Anaheim.