Hurd, who was 62, joined Oracle in 2010 after leaving Hewlett-Packard where he was named one of Fortune Magazine's 25 most powerful people in business in 2007.
A month after he left HP following allegations of sexual misconduct, then-Oracle CEO Larry Ellison named him the president of his company. Hurd then took over for Ellison when he stepped down in 2014.
Hurd has shared the CEO position with former Oracle CFO Safra Catz. When Hurd took his recent leave of absence, Ellison said that Catz would not be the lone CEO for long with Oracle planning to keep its dual CEO structure.
Ellison released a statement Friday saying "Oracle has lost a brilliant and beloved leader who personally touched the lives of so many of us during his decade at Oracle. All of us will miss Mark's keen mind and rare ability to analyze, simplify and solve problems quickly. Some of us will miss his friendship and mentorship. I will miss his kindness and sense of humor."
Oracle shares were down 0.9% to $54.46 on Friday afternoon following the news of Hurd's death. Shares are up about 21% this year.