The infants were discovered by another shopper who heard their cries Saturday through the cracked windows of Jenesia Williams car.
Darlene Marshall was parked next to the Scion. She and her husband were leaving the Ellenwood store, a little after 10 p.m., when she discovered the twins.
Police were waiting for Williams, who was arrested and charged with two counts of child cruelty.
Police spokeswoman Rebecca Brown said the infants were taken to a hospital as a precaution, then released to their father.