The Portugal international was responding after a day of speculation surrounding his future at Santiago Bernabeu, with some reports claiming he had put pen to paper on a new three-year deal.
But Ronaldo took to Twitter to dismiss the claims that he had already signed fresh terms.
"All the news about my renewal is false," Ronaldo wrote.
The speculation came after Madrid president Florentino Perez announced earlier in the week that his intention was to make the Portugal international the highest paid player in the world.
Ronaldo has been linked with a €100million (£85m) move to free-spending Ligue 1 outfit AS Monaco, while former club Manchester United are also said to be monitoring his situation.
In a bid to ward off any interested parties, however, Madrid were thought to be preparing an offer that would see the player earn €80million over five seasons and cost the club €166million in total when tax is included.