G20 members say they expect to begin automatically sharing tax information by the end of 2015.
The system of information sharing forms part of plans to tackle global tax evasion.
In a communique published on Friday, G20 leaders said they would take steps to close loopholes that allow legal tax avoidance by big businesses.
They also pledged to help developing nations tackle tax evasion by helping them track funds in tax havens.
More than 50 countries have signed up to an international convention to facilitate exchange of information on tax issues.
But many developing countries have not signed up, and G20 countries have agreed to share expertise on tracking funds to encourage them on board.
The activities of big businesses that legally avoid large tax bills by moving profits from country to country are also targeted.
The communique said the G20 would be putting forward recommendations to set up a system so that profits are taxed "where economic activities deriving the profits are performed and where value is created".
Away from tax, G20 members also agreed to carefully manage the wind-down of global economic stimulus measures.
In recent days, developing economies have voiced concern that the expected tapering of the US Federal Reserve's $85bn-per-month stimulus programme may have a significant knock-on impact.