Martin Senn, who was head of Switzerland's largest insurer until the end of last year, took his own life on Friday, the group said in a statement on Monday.
The 59-year-old was “not only a highly valued former CEO and colleague but also a close friend,” said the statement.
“Our thoughts are with his bereaved family and friends, to whom we extend our deepest sympathies”.
Senn came to Zurich Insurance in 2006 and was made CEO in 2010.
He stepped down in December a month after the group announced a sharp drop in profits linked to the industrial disaster in Tianjin, China.
At the time Senn said in a statement that he wished to retire and “make way for new management”.
"There have been some setbacks in recent months, but I am convinced that we have put in place the right measures for Zurich to reach its targets," he said.
"I will remain closely tied to the company and am proud of what we have achieved together over the years."
It's not the first time the Swiss insurer has been touched by suicide.
In 2013 its 53-year-old chief financial officer Pierre Wauthier was found dead at his home after taking his own life.
The company's powerful chairman at the time, former head of Deutsche Bank Josef Ackermann, resigned just days after Wauthier was found dead amid speculation that the two had fallen out over the group's accounts.
Ackermann said he had decided to quit because he had reasons to believe that Wauthier's family felt he should take a share of the responsibility, though he underlined that any allegations were unfounded.
Two independent probes meanwhile concluded that Wauthier, a French and British citizen who had served as CFO since 2011, had not been subjected to any "undue or inappropriate pressure", and that "the financial figures were confirmed as appropriate", the insurer said later.