Ferrari accused former technical manager Nigel Stepney on Tuesday of passing secrets to Formula One rivals McLaren.
"Ferrari confirm that we have brought an action against Nigel Stepney and a Vodafone McLaren Mercedes technical engineer in a court in Modena regarding the theft of technical information," a spokesman said.
He said Ferrari had also taken legal action in England against the unnamed McLaren employee.
"A search was carried out of the engineer's house, where we found this information," he added.
Stepney, who has accused Ferrari of waging a dirty tricks campaign against him and denied accusations of sabotage, has been linked to other teams since he fell out with Ferrari following the departure of technical director Ross Brawn.
Ferrari said earlier on Tuesday they had dismissed the 47-year-old.
Ferrari sources said that a significant amount of classified information was involved and they were not ruling out other teams having also received some.