Steve Jobs, chief executive of Apple Inc., will take a medical leave of absence until the end of June, he said Monday.
He plans to "focus on his health" with the backing of the board of directors, he said in a statement. Jobs, 53, did not say whether whether his condition was related to the pancreatic cancer he had battled before.
Chief Operating Officer Tim Cook, who temporarily took over for the chief executive during an earlier medical leave in 2004, will manage day-to-day operations in the meantime, Jobs said.
"I love Apple so much and hope to be back as soon as I can," Jobs said.
Previous bouts of cancer had caused dramatic weight loss that left Jobs looking gaunt and investors fretting. U.S. markets are closed for the Martin Luther King Jr. holiday, but electronically traded stock futures dipped around 1% on the news.
Apple plans to announce its quarterly earnings on Tuesday.