The victims were identified as Kathie Barber, 58, and Gen Miake, 60.
Authorities say Barber called the San Bernardino County Sheriff's Department for help on Saturday at 1:36 p.m. because she had become separated from her husband and could not find him.
She also had run out of water, she said. She was concerned because her husband had a heart condition.
They had been hiking since about 11 a.m.
A search party was organized on the ground and from the air. Crews spotted the two hikers about a mile east of the Amboy trail head. Both were on the ground and unresponsive.
They were about 100 yards from each other in open desert, with no shade in 113-degree heat.
Fire department rescue crews found them on the ground and determined they were deceased at the scene.