At a meeting of the G20 in South Korea, it was decided that around six per cent of the votes in the IMF will be transferred to emerging economies, such as Brazil, Russia, India and China.
The fast-growing nations will also be granted more seats on the board of the IMF, with Western Europe losing two to balance out the increase.
IMF managing director Dominique Strauss-Kahn said: "There will be other reforms, but what we did today puts an end to a discussion on legitimacy that had lasted for years, almost decades."
But the US has retained its 17 per cent stake in voting decisions, effectively giving it a veto on IMF matters.
This is because key decisions require an 85 per cent approval rate from IMF members.
By Tony Aynsley