Oracle co-chief executive Mark Hurd will take a leave of absence for health reasons, the software company announced Wednesday.
In a memo to employees, Mr Hurd said the board had granted him a medical leave of absence after he decided to spend time focusing on his health.
Oracle founder Larry Ellison, who serves as executive chairman and chief technology officer, said he and co-chief executive Safra Catz will cover Mr Hurd's responsibilities during his absence.
"As you all know, Larry, Safra and I have worked together as a strong team, and I have great confidence that they and the entire executive management team will do a terrific job executing the exciting plans we will showcase at the upcoming OpenWorld," Mr Hurd said.
The news came as Oracle reported first-quarter financial results a day earlier than scheduled.
Shares were down 4 per cent in after-hours trading, after rising 1.5 per cent during Wednesday's regular session.