The four - the United States, Russia, the United Nations and the European Union - met in Washington to discuss the "road map" that proposes the creation of two states living side by side.
"The roadmap is not complete yet, but the United States is committed to its completion, we are committed to its implementation in the name of peace," President George W Bush told reporters.
Also on Friday, Israeli Foreign Minister Binyamin Netanyahu met UK Foreign Secretary Jack Straw in London.
Their talks came after the announcement of a British plan to hold discussions with Palestinian leaders next month, a move criticised by Mr Netanyahu.
A spokesman for the UK Foreign Office said Mr Straw and Mr Netanyahu had a "good discussion".
Frustration
The EU had been pushing for the road map peace plan to be published at the Washington meeting, arguing that the whole process needs momentum.
It says time is running out if the 2005 deadline for the creation of a permanent Palestinian state is to be met.
But the US says it wants to wait until after the Israeli general election, scheduled for the end of January, before releasing exact details of the plan.
The BBC's Michael Buchanan says the Washington meeting allows the quartet to demonstrate to the outside world that, while Iraq may be the focus of most international attention at the moment, the continued unrest in the Middle East has not been forgotten.
However, our correspondent says, there is increasing frustration about the role the US is playing.
Speaking earlier this week, EU foreign policy chief Javier Solana bemoaned the lack of a committed American partner in the process.