Aquilani passes medical to complete Liverpool move
Aquilani dispelled fears over the ankle injury that needed surgery this summer and restricted his appearances for the Serie A club last season.
But he will not be fit to face Tottenham next Sunday in the Premier League season opener at White Hart Lane.
Announcing the deal on the club website, a Liverpool statement read: "Liverpool FC confirmed this evening that Alberto Aquilani has successfully completed a medical and agreed a 5-year contract with the club.
"The player will now continue his rehabilitation from an ankle operation under the guidance of Liverpool's medical team and is expected to be fully fit in approximately 4-8 weeks time."
Aquilani is believed to be earning around £80,000 a week.