England boss Roy Hodgson has suggested that Cole's position could be in jeopardy due to his lack of game time this season but Mourinho believes that shouldn't count against the 33-year-old.
"It's Roy's decision," the Chelsea manager told Sky Sports News.
"There are many national team managers, (who) select their players independent of what they do for their clubs - players who don't play at their clubs but have the complete trust of their national team managers.
"I think Ashley Cole did very well for England in the qualification, he's one of the boys who gave an important contribution for England to be in the World Cup.
"Normally, I don't see any reason for him not to be selected for the World Cup.
Baines a contender
"Is he an important player for me and for Chelsea? Yes, he is.
"At this moment, he is not playing so regularly, but he is in great form and he is ready to go with the national team."
It has been suggested that Everton's Leighton Baines rather than Cole is Hodgson's preferred choice at left-back for England at the moment.
Baines has featured more for his club side than Cole this season, playing 19 games to Cole's 13, and has also chipped in with three goals.
Southampton's Luke Shaw, Arsenal's Kieran Gibbs and Danny Rose of Tottenham are younger players who are likely to come into the reckoning at some point.
The Chelsea manager also insists the subject of John Terry playing for his country again should not be under his discussion.
Hodgson this week made a concerted effort to end any talk of Blues central defender Terry coming out of international retirement.
Terry's form has been so good this year that Gary Lineker, among others, called for the Chelsea skipper to come back to the international fold.
But Mourinho believes Terry's retirement from England duty will benefit Chelsea.
"It's a waste of time to keep speaking about the situation," Mourinho said.
"Roy Hodgson is the person to kill the discussion or to feed it. End of story.
"I'd never intervene. He's in charge and has everything in his hand. He has made that decision.
"For me as a Chelsea manager I'm happy players play with their national teams - but at the same time I'm happy an important player like him is fully focused on his work at Chelsea."
The Blues - as well as second-placed Arsenal and third-placed Manchester City - all have two-legged Champions League last-16 ties coming up and Mourinho feels this could play into Liverpool's hands in the Premier League title race.
He said: "When I say we're not the top candidate everyone thinks 'here he is again, with what you like to call the mind games'.
"But it's just my feeling.
"The league is amazing - it is difficult for every one of us.
"There are teams with more potential than others, obviously. There is another, like Liverpool, with a big advantage with the fact that they don't play in the Champions League.
"Playing in this is going to take concentration and energy from the teams that are involved in it. I think it will be good fun."