Widespread reports have claimed that Ronaldo would be open to returning to Old Trafford following his departure back in 2009.
However, Ancelotti has insisted that the 29-year-old, who won the Ballon d'Or in January, is "happy" playing for the European champions.
"These are words without meaning." FourFourTwo quotes Ancelotti as saying. "I believe [the] reports are nonsense. Cristiano is happy here, very motivated to be here, and all Madridismo is delighted with him.
"Ronaldo [has] great professionalism, leadership, we must enjoy him and do everything to keep him in this physical and mental condition. Without doubt Ronaldo is the best player in the world. We are lucky he plays for us. We have to enjoy it."
Reports have claimed that it would cost £200m in fees and wages for United to bring Ronaldo back to the Premier League.