"Cristiano Ronaldo is fine... He will play against Valencia," Mourhino told a news conference.
Real said on Wednesday that Ronaldo had an inflamed tendon in his right ankle. The 25-year-old striker, the world's most expensive player, took part in Real's humiliating 5-0 pasting by arch-rivals Barcelona on Monday.
The 2008 FIFA World Player of the Year has started all 13 league matches this season as well as all five Champions League matches, and scored a total of 18 goals.
Real are in second place in the league with 32 points, two fewer than Barcelona, following their loss to the Catalan side.