Moody made his first appearance for Leicester Tigers in 1996 and played 223 games for the club from August 1996 until his farewell appearance in the 2010 Premiership Final before joining Bath.
He gained 71 caps for England and played in three Tests for the British and Irish Lions, won seven Premiership titles and two Heineken Cups with Leicester, an Anglo-Welsh Cup, two Six Nations Championships and a World Cup winner’s medal in 2003.
''It is with great sadness that I have to announce my immediate retirement from all forms of rugby. I have been very privileged to have played in some incredible teams and with some phenomenal players,” he said.
"I owe a huge debt of gratitude to all the medics and physios who have put me back together time and time again to enable me to continue to play this wonderful sport of ours.''
"I would like to thank all of the coaches that I have worked with during my career, from Bracknell minis to the British and Irish Lions; they have all left their mark on me as a player.''
"It goes without saying how much I value the fans who have supported me so loyally over the years, it has been one of life's singular pleasures to have played this game in front of you.
"Finally, I would not have achieved what I have in this sport without the continued support of my family and friends during my entire career. Rugby has been my life for such a long time now, 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.''
Former Tigers and England captain Martin Johnson said: "When I look back at playing with Lewis it always brings a smile to my face – it was never dull.
“He was one of the most committed guys I ever played with and had a complete disregard for his own physical wellbeing. It's sad that he has had to retire but he should be remembered for a great career and someone who never gave less than 100 percent for his club and country."