Fabrice Muamba says he is devastated at being forced to retire from football.
The Bolton midfielder suffered a heart attack during a game in March and has made his decision following medical advice.
Muamba, 24, had hoped to make a comeback to the sport, but following extensive consultations with leading cardiologists, he will not be re-joining the Championship club.
In a statement on the club's website Muamba said: “Since suffering my heart attack and being discharged from hospital, I have remained utterly positive in the belief I could one day resume my playing career and play for Bolton Wanderers once again.
“But the news I received was obviously not what I had hoped it would be and it means I am now announcing my retirement from professional football.
“While the news is devastating, I have much to be thankful for."