Commonwealth leaders have urged richer countries to "give more than they receive" at upcoming world trade talks.
Commonwealth countries account for some 30% of world trade
At their Malta summit, they asked for a demonstration of "political courage and will" in the negotiations, particularly over agriculture and market access.
The statement came at the end of what Commonwealth head Don McKinnon called a "no-holds barred" debate.
A BBC correspondent says the message was aimed mainly at the EU, which was criticised for keeping farm subsidies.
In their statement, the leaders urge developed countries to "demonstrate the political courage and will to give more than they receive... particularly in the negotiations on agriculture and market access, as their own longer term prosperity and security depends on such an approach".
They go on to say they recognise "developing countries must also demonstrate flexibility and commitment to ensure a successful outcome to the round".
But they say extra support should be given to countries that are hard hit by trade liberalisation, particularly those that have been dependent on preferential trading arrangements.
They specifically call for transitional help for smaller Commonwealth countries hit by the EU's sugar reforms.
On Friday, a number of Commonwealth Caribbean nations protested about a 36% cut by the EU to the guaranteed price of sugar.
The statement is quite an achievement for the Commonwealth given the strains over the issue during this summit, and a particular triumph for smaller, poorer members, says the BBC's Nick Childs in Malta.
They will be hoping that this declaration, from a group of nations that accounts for some 30% of global trade, will have an impact, he adds.
"The desire is to ensure that something can happen," said Mr McKinnon. "And there is a high expectation in here that the EU will do more than what the EU is currently saying they will do"
The spotlight will fall on UK Prime Minister Tony Blair - both a Commonwealth member and the current EU president - in the coming days to see how he will use this message, our correspondent says.
Sugar producers in the Caribbean are angry at EU price cuts
Earlier, Mr Blair warned it would be disastrous if the World Trade Organization talks, due to be held in Hong Kong next month, failed to come up with a deal on fair trade.
"This is an absolutely critical moment of decision for the whole World Trade Organization. If we don't get significant movement in Hong Kong and subsequently there is a danger that the round fails. That would be disastrous for economies, both developed and developing," he told journalists in Malta.
Two other Commonwealth members - Malta and Cyprus - are also EU members.
The 53 members are due to spend the last day of their three-day summit discussing political issues as they prepare to issue a final communique.
Mr McKinnon confirmed the next summit would go ahead as planned in Uganda in 2007, despite concerns among Commonwealth members at the arrest of opposition leader Kissa Besigye.
He said he was confident that Ugandan President Yoweri Museveni would resolve the matter as quickly as possible. Dr Besigye's supporters say the charges are politically motivated, coming as they do ahead of presidential elections next year.