It happened around 5:50 Friday afternoon on the 900 block of DuPont Street in Wilmington.
Authorities say the 77-year-old woman left her car with the keys still inside as she went into St. Anthony's Church.
An unknown suspect drove away with the woman's vehicle and her dog "Noel" was still inside.
The car was later found early Saturday morning on the 200 block of North Connell Street but the dog is still missing.
The victim is especially concerned because her pup reportedly suffers from cataracts and partial blindness.
Anyone with information on the incident on the whereabouts of "Noel" is asked to call the Wilmington Police Department's non-emergency number at 302-654-5151.