Prosecutors in Morelos state said a relative identified the body of Father Moises Fabila Reyes, 83.
He appears to have died of a heart attack and is the third priest killed or to have died under suspicious circumstances in Mexico in a week.
The prosecutors' office said relatives had reported that Fr Fabila Reyes was missing to federal anti-kidnapping prosecutors in Mexico City.
The Catholic Multimedia Centre said the priest had been on holiday when he was abducted on April 3 and that family members paid a ransom of over 100,000 US dollars.
In the last week, a priest was shot dead on the outskirts of Guadalajara and another was stabbed to death outside Mexico City.
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