The former film star was accused of embezzling about $80m before he was forced from office by street protests in 2001.
Estrada was also ordered to forfeit a mansion and more than $15.5m. He will serve out the sentence under house arrest on his country estate.
He described the verdict as a political decision by a kangaroo court. Estrada was found not guilty of a separate charge of perjury.
His son Jinggoy was acquitted of the charge of plunder.
There was tight security in the Philippine capital, Manila, as Estrada’s supporters were kept several blocks away from the courthouse.
A spokesman for President Gloria Arroyo called for calm. “We hope and pray that the rule of law will prevail,” Ignacio Bunye said, quoted by AP.
“Meantime, we have a country to run, an economy to grow and a peace to win. We hope that this sad episode in our history will not permanently distract us from this goal.”