Moody played more than 220 games for Tigers from his debut in August 1996 to his farewell appearance in the 2010 Premiership Final victory over Saracens before joining Bath.
Chairman Peter Tom said: “Lewis came into the Tigers squad straight from Oakham School and quickly made an impression with his fearless and all-action performances.
“He was a member of the most successful teams in this club’s history and also represented Leicester Tigers on the world stage with England and the Lions.
“He has always been extremely popular with team-mates and supporters alike, and he will always be a welcome visitor to Welford Road.”
Cockerill, a former team-mate in the Tigers forward pack, said: “Lewis was a major part of the Leicester Tigers squad and the culture here for 14 years and he enjoyed a great deal of success in that time.
“He always put his body on the line for the good of the team and his colleagues, and that made him a very important members of the squad over a long period.
“The way he overcame a number of serious injuries also spoke volumes for the dedication and commitment he gave to the game.
“He won everything there is to win with Leicester, won the World Cup with England and led his country as captain which is the ultimate honour.
“On behalf of everyone at the Tigers, I would like to wish him well for the future and I’m sure he will take the same enthusiasm he has for rugby into his future off the pitch.”
Moody scored 36 tries for Tigers, winning seven Premiership titles and back-to-back Heineken Cups. He was awarded an MBE following England’s Rugby World Cup win in 2003, he has gained 71 senior caps and played in three Tests with the British & Irish Lions.
''It is with great sadness that I have to announce my immediate retirement from all forms of rugby,” Moody announced today.
“I have been very privileged to have played in some incredible teams and with some phenomenal players.
"Rugby has been my life for such a long time, it is scary to imagine what it will be like without it, but I look forward to relishing the new opportunities and adventures that will come my way.''