Lee, 36, was keen to return to the court post treatment. The shuttler, who spent a total of 348 weeks as world number one announced his retirement in a teary-eyed press conference.
"My decision to retire is a heavy one. I really love this sport. But it is a demanding sport," Lee told mediapersons. He further said that he would now like to rest and spend time with his family, and even take his wife on a 'honeymoon'.
A father of two, Lee was diagnosed with early-stage nose cancer last year and had received intensive treatment in Taiwan.
"I have no regrets. More important is my health, the decision to retire is very tough," said Lee.
Lee also informed that his cancer treatment was now over. "My plan to retire was originally after the Olympic Games. I made this decision due to my health," he explained.
Terming Lee as a 'legend', Badminton Association of Malaysia (BAM) Chief Norza Zakaria, who was also present at the presser, said: "It is a sad day. Lee is a legend and very dependable. We accept his decision."
Earlier in 2018, Lee had bagged gold at the Commonwealth Games in Gold Coast (Australia). He has won 69 international titles and is a three-time Olympic silver medallist.
( With inputs from IANS )