The Croatia international - who played against Australia during the 2006 World CUp - believes it is time to move on after playing 144 games in the Bundesliga, scoring 13 goals.

"After eight years at Bayer 04, I am now looking for a fresh challenge," he told the club's website.

"I have a lot to thank this club for as it is here that I have become a full international."

The 26-year-old moved to the Bundesliga from NK Osijek in 1999. He played in the Bayer team which lost the final of the Champions League in 2002, as well as finishing runners-up to Borussia Dortmund in the league and losing the German Cup final in the same year.

A first-team regular since the start of the 2002/03 season, Babic earned his first cap for Croatia in May 2002 and represented his country at Euro 2004 and last summer's World Cup.

Spain looks to be his most likely destination with Real Betis leading the chase for his signature.

Leverkusen's director of sport Rudi Voller accepted Babic's decision to move on.

"I perfectly understand Marko Babic's decision," he said. "He has done a lot for us in these years and for his personal and sporting development, this can only be an advantageous step."

Leverkusen are also set to lose defender Juan and goalkeeper Hans-Jorg Butt at the end of the season.