The winger has been in scintillating form for Tottenham this season but was forced off halfway through Friday's 2-1 victory against Scotland after failing to recover from a virus
The 23-year-old was substituted midway through the 2-1 win over Scotland on Friday after aggravating a previous ankle injury and failing to fully overcome an illness.
Wales manager Chris Coleman had earlier insisted that Bale would not be risked for the clash with Igor Stimac's men if he were below full readiness but revealed on Monday that the Tottenham star is fit for the Group A game.
|5/2||Gareth Bale is 5/2 with BetVictor to score anytime in Wales v Croatia
A loss on Tuesday would see Wales fall 10 points behind the second-placed Croatia in their quest to qualify for World Cup 2014 and the manager believes that his squad will have to be at their very best against a side boasting the likes of Real Madrid playmaker Luka Modric.
"Croatia have impressed me the most - offensively they're very aggressive and they're quite physical," Coleman added, "and obviously they've got a guy in the middle of the park, Luka Modric, who would grace any team.
"This will be a very tough game for different reasons than Friday but we've got to play our own game. We passed the ball very well at Hampden Park and were very exciting. We have to have that same philosophy.
"Sometimes you get results and sometimes you don't but the important thing for Wales is that we've got a style of play we're trying to evolve."