The chair of the Co-operative Group says the unanimous vote in favour of wide-ranging reforms as a "highly significant moment" for the mutual, which slumped to £2.5 billion annual losses after a period of crisis.
Ursula Lidbetter said: "I am delighted that our members have made clear their commitment to far-reaching reform of our governance with this unanimous vote.
"There is a huge task ahead of us if we are to deliver the reforms necessary to restore the Group's reputation and return it to health but the board will work hand-in-hand with our members to ensure that we seize this opportunity.
"It is vital that the right changes are put in place as soon as possible to build a more effective organisation for our members, customers and colleagues."
More top news
David Cameron has apologised for experiencing "brain fade" after he forgot which football team he supports.
Fans can finally have their first look at Jared Leto's incarnation of the classic villain in 2016's Suicide Squad
Labour is promising to reverse the Conservative policy of privatisation in the NHS which it claims is creating longer waiting times.