A Northern California couple has gone to jail because they left their newborn child in a car while attending a casino.

The baby girl was discovered in the underground parking lot of the Thunder Valley Casino.

A judge has sentenced Thuan Huy Nguyen and Panfila Phu Phan to to 60 days in jail for the offence and has also ordered them to do four years probation, during which time they must attend mandatory parenting classes.

The couple was arrested in April after a security guard at the Thunder Valley Casino found their seven-week-old infant in the car.

The baby had been left for about two-and-a-half hours while the parents gambled inside.