Firefighters were alerted when the woman rang 999 after she was trapped up to her knees on an area of land near Chercombe Bridge at Bradley Barton.
One crew from Newton Abbot, the specialist rescue team from Exmouth and environmental protection unit as well as a support pump from North Tawton went to the scene.
The woman, who was walking two dogs, had become trapped in the mud in a field which contained 20 cows who had surrounded her and were only about five feet away.
Fire control staff remained on the phone to the woman to keep her calm and help guide firefighters to her location.
After 25 minutes, the woman had been freed from the mud by firefighters using a salvage sheet and wading poles.