The 71-year-old singer announced on his website Monday that he is calling off the North American leg of his No More Tours II tour in order to seek medical treatment in Europe.
Osbourne had rescheduled the North American leg in November after postponing the tour in 2019 due to illness and injury. The leg was to begin May 27 in Atlanta, Ga., with special guest Marilyn Manson.
"I'm so thankful that everyone has been patient because I've had a [expletive] year," Osbourne said. "Unfortunately, I won't be able to get to Switzerland for treatment until April and the treatment takes six-eight weeks."
The post said Osbourne made the decision now in consideration of fans with tickets to the rescheduled shows, some of whom have been asked to change plans multiple times.
"I don't want to start a tour and then cancel shows at the last minute, as it's just not fair to the fans," Osbourne said. "I'd rather they get a refund now and when I do the North American tour down the road, everyone who bought a ticket for these shows will be the first ones in line to purchase tickets at that time."
Refunds are available to ticket holders at the original point of purchase. Fans who purchased No More Tours II tickets will have first access to tickets when Osbourne's next tour is announced.
Osbourne did not indicate if the U.K. and European leg of his tour is also canceled. The leg is scheduled to begin Oct. 23 in Newcastle, England.
Osbourne went public with his Parkinson's disease diagnosis on Good Morning America in January. He attended the Grammy Awards with his wife, Sharon Osbourne, and daughter Kelly Osbourne following the news.