The country's leader, a fan of Real Madrid, believes the Portuguese deserves to win the prestigious prize for the year's finest footballer ahead of Lionel Messi and Franck RiberyReal Madrid forward Cristiano Ronaldo to win the Fifa Ballon d'Or.
Madrid fan Rajoy, who is the leader of Spain's People's Party (Partido Popular) and has been in government since December 2011, revealed he would vote for the Portuguese ahead of Barcelona's Lionel Messi and Bayern Munich's Franck Ribery.
"As a madridista, if I had to vote, I would give it to Cristiano Ronaldo," he said in an interview with Radio Nacional de Espana.
On the other two top contenders for the prestigious prize, the 58-year-old added: "Messi had a magnificent season and Ribery won everything."
Meanwhile, Madrid legend Raul has also lent his support to his former team-mate in the build-up to the award, which will be handed out in Zurich early next year.
"Cristiano Ronaldo is the best player in the world," the forward told reporters at an official event organised by his club in Qatar, Al Sadd.
Ballon d'Or voting has been extended by Fifa to November 29, with those who have already voted also permitted to change their selections.