Investigators say Sebastian Mosqueda and his mother Monserrat Caracoza, 18, were kidnapped by the boy's father just before 2 a.m. from their Porterville home.
The suspect, 23-year-old Pedro Mosqueda, allegedly climbed through a window and took the boy, and the mother was abducted when she ran after them.
A motive for the abduction has not been released. Mosqueda was wanted on two warrants alleging domestic violence.
The boy weighs 12 pounds and has brown hair and brown eyes. The mother was described as 5 feet 2 inches tall, 130 pounds, with brown hair and brown eyes.
The suspect was last seen driving a red 1991 Honda Civic with a California license plate of 5VOY539. If you see the vehicle, the suspect, or the mother and child, you are urged to call 911.
The Associated Press contributed to this story.