Sergio Aguero has retired from football at the age of 33 due to a heart condition.
The Barcelona striker announced the news at a press conference at the Nou Camp on Wednesday morning, where he addressed the media alongside club president Joan Laporta.
An emotional Aguero said: "This conference is to communicate that I have decided to stop playing football.
"It is a very difficult moment. The decision I have made I have taken for my health, that is the main reason, because of the problem that I had a month-and-a-half ago.
"I was in good hands of the medical staff who have done their best and have told me the best thing would be to stop playing.
"So I made that decision about a week ago and I want to tell everyone I did everything possible to have hope, but there wasn't very much."
Aguero experienced chest pains and breathing difficulties during the first half of Barcelona's 1-1 home draw with Alaves on October 30.
He fell to the turf clutching his chest and was treated for several minutes before being able to walk off and taken to hospital.
The Argentinian was subsequently diagnosed with a cardiac arrhythmia (irregular heartbeat).
The former Manchester City and Atletico Madrid striker continued: "I am very proud of the career I have had, very happy.
"I always dreamt of playing football from five years old. I want to show my gratitude to everyone, all of the clubs I played at and, of course, my love, Argentina.
"I don't know what awaits me in the next life, but I know there are a lot of people who love me and want the best for me."
Barcelona president Joan Laporta, who sat on stage beside Aguero during the press conference, paid tribute to the summer signing and expressed regret at him making only five appearances for the club.
"It is as if all the reps of the teams you have played for are right here next to me too. We are left with the joy and excitement of what you could have been here at Barca," said Laporta.
"On your first day at Barca, we wished you had come here earlier. We always wanted you to play for our club but a new journey awaits and I hope it will be just as successful, you deserve it.
"You have all of our support, anything you need we are here at your disposal.
"You have been an amazing player and everywhere you have played you have achieved so much, not just the talent but also the friendships you made."
The press conference ended with Aguero receiving a standing ovation.
Aguero signed for Barcelona in the summer after 10 years at Manchester City, where he became a club legend, scoring 260 goals in 390 appearances.
His haul of 184 Premier League goals places him fourth on the list (since 1992) behind Alan Shearer, Wayne Rooney and Andy Cole.
He won five Premier League titles while at Man City, his most memorable intervention of all coming in their first title winning campaign in 2011-12, when his goal deep in injury-time against QPR delivered the blue half of Manchester City its first league triumph in 44 years, snatching the championship away from their neighbours Manchester United in one of English football's most dramatic finales.
Manchester City chairman Khaldoon Al Mubarak paid tribute to Aguero's career with a message on the club's website, saying: "The facts speak for themselves - Sergio is quite simply the most ruthless striker in the history of the Premier League.
"It is extraordinary that his statistics, more reflective of two careers, are in fact those of a player whose time in the game was cut short.
"His impact lives not only in the club that we are today, but in the club that we will be for many years to come.
"He has earned the adoration of the City family, and the respect of the football family the world over."
Aguero began his career with Independiente in his native Argentina before signing for Atletico Madrid in 2006, scoring 102 goals in 234 appearances for the Spanish club. He scored 41 goals in 101 appearances for the Argentinian national team, playing in three World Cups.
He helped Argentina win the Copa America earlier this year, while in five matches for Barcelona Aguero scored once, in a 2-1 defeat to Real Madrid.
