Wyman Bryant and his younger sister Willow went missing Aug. 14, and an Amber Alert was issued by the California Highway Patrol a few days later.
On Friday, authorities said they located the siblings and deactivated the Amber Alert. The Sheriff's Department also told Eyewitness News that the children's parents have been taken into custody.
Further details on how and where the children were found were not immediately available.
Tiffany Bryant, 39, and David James, 53, allegedly took the children during a supervised DCFS visit in South L.A.
Nina Glass, the director of a Texas-based nonprofit that helped out in the search, said Bryant and James left with Wyman and Willow through an emergency exit and left behind their 15-month-old child.
The children had been with a foster family since last year after the baby tested positive for drugs in their system at birth.
Glass said this was the second time the couple had taken their children. The first incident happened last summer when their third child was born, and they were found two months later. They were apparently granted visitation rights again after that.
Authorities believed they had been traveling in a champagne-colored Buick Enclave SUV with paper plates.