Lazio striker Klose, who is five goals short of Gerd Mueller's German record of 68 international goals, missed five weeks towards the end of last season with a thigh injury.
The 33-year-old, who will be playing in his sixth consecutive international tournament, took part in Germany's two warm-up games and has allayed fears he will not be able to give his all in Poland and Ukraine.
"I'm right on schedule and I am pain-free," Klose told a press conference on Tuesday.
Joachim Low's side are among the favourites to win the competition and Klose is confident of success, despite their extremely difficult group which also features Portugal, Holland and Denmark.
"I have a very good feeling we are well prepared and have a great team," added Klose, who turns 34 on Saturday when Germany face Portugal.
The Portuguese are third favourites to progress from the group due to their supposed over-reliance on Cristiano Ronaldo and Klose has warned this weekend's opponents they will have to work hard to beat the three-time European champions this weekend.
He added: "Portugal is not only Cristiano Ronaldo, they must also play as a team. If they want to beat us, they do it only as a team."