The 25-year-old Portugal international spent six years at Old Trafford where he became a leading player for the Red Devils.
He won three Premier League titles with United, as well as the UEFA Champions League in 2008, before completing a big-money move to the Bernabeu last summer.
Ronaldo switched to Madrid for a world-record £80million transfer fee, and has carried his excellent form into the Spanish league, although he could not take Real to the La Liga title last term.
He admits he does miss Manchester, but does not expect to return to the club at any time in the future.
"Yes, of course I miss Manchester," he said in the Daily Mirror.
But when asked if he would consider the possibility of a return to his former club, he remarked: "No, I don't think I'll be going back."