However, the 22-year-old signed a five-year contract extension this summer that will keep him at United until 2012, and he confirmed in an interview with Spanish newspaper Marca that he sees his long-term future at the Premier League champions.
When asked his thoughts on Real Madrid, Ronaldo said: "Real Madrid are a great club, everybody knows that. But I insist that I am very happy at Manchester United and I want to continue here for many years."
No player playing in England has ever won the FIFA World Player of the Year award though - which is in stark contrast to both Spain and Italy - but Ronaldo dismissed any suggestion that playing in the Premier League hindered his chances of winning an award like that.
"Not at all. I think that the English league since last season is the strongest, above the Italian and Spanish," said Ronaldo, who is an outside bet to pip AC Milan playmaker Kaka to this year's FIFA World Player of the Year.
"In England all the stadiums are full and any smaller team can now win against the big teams. As well as that, the play is not stopped so many times, it is very fast, intense and aggressive, and the players are stronger," he said.
"The Spanish league is also a very good league. I like it very much and I have a lot of interest in it, but I think that right now the English league is better."