The Portuguese was asked by Sportbox.ru about a possible move to Russia, after Samuel Eto'o's big money move to Anzhi Makhachkala from Inter Milan earlier this summer, and admitted he would consider a similar transfer.
Speaking at the global premier of the Castrol EDGE presents 'Ronaldo Tested to the Limit' documentary in Madrid, the winger admitted: "Why not? I know that the Russian football championship is becoming stronger and I have no objections to someday be playing in your country.
"In football, you never know what will happen. So if I end up in Russia, one shouldn't raise his eyebrows in surprise," he added.
However, he admitted that a possible move could be done much later in his career, adding: "At the moment I'm quite comfortable with Real."
Ronaldo has been in fine fettle so far this season in La Liga, scoring four goals in two appearances against Real Zaragoza and Getafe to lead his club to the top of the table.