The former Argentina and Italy international has been a popular acquisition to the Welford Road ranks since moving from French club Brive during the summer of 2005.
After leaving his home country a decade ago to experience professional club rugby in Europe, Moreno has seen service with Agen, Perpignan and Brive in France, as well as with Worcester and Tigers in England.
After a dozen games in his first season with Tigers, Moreno has added another 11 games in the current campaign during which he has also played a big part in helping his fellow Argentina-born forwards Marcos Ayerza and Martin Castrogiovanni settle into new surroundings following their arrival in the summer.
Tigers head coach Pat Howard, who last week also revealed new contracts had been signed by home-grown players Dan Hipkiss, James Hamilton and Tom Croft, said: "Alex has been a fantastic addition to the squad, not only for the work he does on the field, but also with his enthusiasm off the field. He is great for the squad and for the club, and he is an important member of our Argentinian contingent."
Moreno, who made his first appearance at Welford Road in the colours of Italy during the 1999 World Cup, made his Tigers debut on the opening day of last season in a 32-0 victory over Northampton Saints shortly after his arrival.
He also started this season's first game against Sale Sharks before a calf injury put him on the sidelines until the autumn international period when he returned to first-team action.
Moreno said: "I am very happy to agree a new contract here. It is perfect for me to stay. It has been a very good move for me to come to Leicester. This is one of the best clubs in European rugby and there is a great group of players here."