Peter Pumpkin was stolen from the Neat Marsh Road area of Preston at around 11.30pm on Saturday, July 17.
His devastated owners contacted Humberside Police who issued an urgent appeal to find him after it was revealed he required daily medication.
Sadly, Peter Pumpkin was located in a dyke not far from his home on Tuesday evening.
Sergeant Julie Fenton said: “We are truly saddened to announce that Peter was located deceased, in a dyke not far from his home address in Preston.
“We would like to thank everyone involved in the search for the missing pony, the family of Peter have been overwhelmed by the generosity of the local community .
“My heartfelt condolences go to his owners following their tragic loss.
"We are continuing with our enquiries into his disappearance, and would ask that anyone with any further information contact us on 101 quoting ref 16/72507/21."