Officials say Kailey Stewart and Hayden Stewart were abducted by their mother, Elmeran Stewart, Friday night around 6:30 in the Rockville Fairfield area.
That's in the northeast portion of the Bay Area.
Kailey is 5-years-old and as blonde hair and blue eyes. She is three feet tall and weighs 40 pounds.
Hayden is 10-years-old and has blonde hair and blue eyes. He is four feet tall and weighs 70 pounds.
Authorities say Elmeran Stewart also goes by the name Casondra.
The 40-year-old is believed to be driving a 1992 Toyota Corolla.
It's red with numerous dents and a different colored red hood.
The license plate is 4YBN892.
If you have any information please call the Solano County Sheriff's Department at area code 707-421-7090.