The boy, known only by his initials RGV since he is a minor, had a long-awaited emotional reunion in an army barracks in Kimberi, in the Cusco area yesterday, the military disclosed.
He told reporters that on January 4, he ran away from the rebel camp where he had been held and ran into an army patrol.
His mother, 32-year-old Maria Vargas, said he was kidnapped at just six months old on August 30, 1996 in Vizcatan, in the area where the rebels had set up operations.
The Maoist-inspired rebels have been largely wiped out except in remote areas of Peru's southeast. Authorities said it was not unusual for them to abduct children to try to indoctrinate them.