Italian Trulli joins the Malaysian-backed team from Toyota, while Finn Kovalainen moves across from McLaren where he was replaced by world champion Jenson Button.
The pair, who have raced in over 250 grand prixs between them, have both signed three-year deals with Malaysian rookie Fairuz Fauzy named as the third driver.
“[The driver team] shows our seriousness to be a world championship contender,” said Lotus team principal Tony Fernandes.
“Trulli will bring us a lot of experience to develop the team, and Heikki is a young driver but has phenomenal experience so I think we have two fantastic drivers with Fairuz as well.”
Trulli, who like Kovalainen, has one race win to his name, insists he has joined the team to be competitive in 2010. “I am here to win the 35-year-old said. “I will fight for the team and for Malaysia. It is a privilege to sign for the new Lotus F1 Racing team.”