The former BLACK SABBATH singer has headlined the travelling festival for ten years, but has decided to allow younger stars to take the limelight in future.
Osbourne will still perform a few shows during tours starting from next year (06).
According to MTVNews.com, a statement from his publicist reads: "After 10 years, the Ozzfest's name and reputation have been established. It's time for me to move on and do other things. Ozzfest will carry on in 2006, however Ozzy will limit his performances to only a few, select cities."
The decision may have been prompted by a throat problem that has caused Osbourne to pull out of a number of shows recently.
Osbourne reportedly stormed off stage in Tacoma, Washington state on Friday (12AUG05) after his voice began to fail.
A review in local newspaper the News Tribune reads, "Osbourne's voice cracked hideously during that number, and he responded by slamming his mike down and storming offstage. The rest of (the band) remained cool and professional, continuing to jam until Ozzy could pull it together and return. He explained himself once the number had ended. 'My voice is ... blown out again,' he said, promising to go on if the crowd wanted to hear him."