While details of the 24-year-old's deal have not been revealed, Tigers boss Richard Cockerill has previously said the offer would make Tuilagi among "the highest paid players in the world".
He has not played for almost 14 months because of injury, missing the World Cup, but could return before January.
Tuilagi is the fourth Tigers player to agree a new deal on Monday.
Fellow England internationals scrum-half Ben Youngs and fly-half Freddie Burns joined club captain Ed Slater in extending their stay at Welford Road.
British and Irish Lion Tuilagi, who has been capped 25 times by England, is Leicester's biggest coup, with the centre previously having been linked with moves to several clubs, including Saracens, Worcester and Toulouse.
"Manu has had very close connections to the club from a very young age and he is a big part of the Tigers family," Cockerill told the club website.
"The club has been very good to him and he has shown huge loyalty to the club in return in wanting to stay here.
"Manu is in the prime of his rugby life at 24, he has very good players and a good coaching team around him here and he is very keen to play his part in the squad."
England centre Manu Tuilagi has agreed a new deal to stay at Leicester Tigers, the Premiership club have confirmed.