The bicyclists, a husband and wife, were riding north on Foothill Road around a quarter mile south of Golden Eagle Way shortly after 1 p.m. when they were struck by a northbound car, according to Lt. Brian Laurence.
The wife was thrown from her bicycle and pronounced dead at the scene, while the husband was taken to a hospital with non-life threatening injuries, Laurence said.
The driver, an 18-year-old Pleasanton resident, stopped at the scene. The cause of the collision is under investigation. The identities of the victims and the driver have not been released.
Anyone with information on this crash is asked to call Pleasanton police at (925) 931-5100.