Assaidi was in the final year of his contract and moves to Anfield after turning down an offer to stay in Holland from Ajax. He was also wanted by Spartak Moscow and Galatasaray.
Playing for the jersey: New signing Oussama Assaidi poses with his Liverpool shirt
He told the Reds' website: 'I'm very
happy to play for this big club. The first time I spoke to the coach I
had a good feeling. I had offers from other big clubs but I've been
waiting for this moment.
'When I watch Liverpool it's always a good atmosphere, the fans are fantastic and I'm happy to be here.'
Fulham had expressed an interest in the pacy Assaidi, who can operate on the flanks or through the middle.
Everything seems to be in order: Assaidi is put through his medical by club doctor Zaf Iqbal
'He fits our style perfectly, he's an exciting player who is very good in one-versus-one situations and I think he's a player that will excite the crowd.
'We're not expecting too much too early, he needs time to adapt but we're delighted he's chosen to come here over a number of other clubs.
Welcome to Liverpool: Anfield manager Brendan Rodgers greets new boy Assaidi
He has 22 caps for Morocco.