The Cote d'Ivoire midfielder says his former clubis "the best team in the world", and says that he would not think of leaving Manchester City to join los Blancos
Toure had a trophy-laden spell in Spain, playing 74 times for the Spanish giants and winning seven competitions including two Liga titles and the Champions League.
However, when asked whether he would consider a move to their fierce rivals Real Madrid, Toure insists that it was something that had not crossed his mind.
"I've never considered going to Madrid because I've been a Barca fan for may years," Toure told RAC1. "Madrid are a great club but it would be very hard to play against Barca.
"Barcelona have always been the most important team to me. They're an example for hard workers and committed players like Xavi and [Carles] Puyol, but also for the fans. They're the best team in the world."
The Spanish giants were rumoured to be interested in Toure's City team-mate Sergio Aguero recently, and the Ivory Coast international admits that turning down the Camp Nou would be a tough choice to make.
"It's difficult to say no to Barca," he added. "You can't say no to playing with Xavi, [Lionel] Messi and [Gerard] Pique. The arrival of [Ferran] Soriano and Txiki [Begiristain] helped a lot. Txiki is a great professional and I'm sure the club will continue to grow with them. Hopefully we can reach Barcelona's level one day."
Toure says that despite the Blaugrana facing a "difficult" tie against Bayern Munich in the Champions League, he fancies his former side to progress.
"The game against Bayern will be very difficult, but Barca are always favourites for me," he continued. "There are always difficulties in the Champions League, like against Milan, but I believe that Barca's quality - and Messi's above all - can decide the game."