Guards opened their cells on Friday morning to find only dummies made of rags and cardboard lying where the men should have been.
Italian media reports quote police as saying Leitner must have had outside help to make such a clean getaway.
Blushing prison officials in the northern Italian city of Bergamo refuse to say how the 45-year-old professional thief and his latest partner in crime managed to escape.
Caught only a year ago hiding in a cornfield, Leitner had famously escaped from an Austrian prison after a heist on an armoured car in 1990.
Later captured by Italian police, he was quoted by media as saying: "Austrian prisons are medieval. It's better in an Italian prison."
By Just Us 19 October 04
