Thousands of houses were destroyed in Gaza during the fighting
International donors have pledged almost $4.5bn (£3.2bn) in aid to the Palestinians, chiefly to rebuild Gaza after Israel's recent offensive.
US Secretary of State Hillary Clinton said Washington would donate $900m, and vigorously seek to advance peace.
Palestinian leader Mahmoud Abbas told a summit in Egypt cash was "insufficient" without a political solution.
Israel, which has been fighting Gaza militants, refuses to allow building materials into Gaza for reconstruction.
As well as the $900m promised by the US, Saudi Arabia pledged $1bn (£703m) for Gaza.
Egyptian Foreign Minister Ahmed Aboul Gheit says the total of $4.48bn from about 70 countries was "beyond of our expectations".
Hillary Clinton announces US pledge
The Palestinian Authority had requested only $2.8bn (£2bn).
Mrs Clinton told the conference in the Red Sea resort of Sharm el-Sheikh: "Our response to today's crisis in Gaza cannot be separated from our broader efforts to achieve a comprehensive peace."
During her first visit to the Middle East as top US diplomat, she said the aim of the aid was to "foster conditions in which a Palestinian state can be fully realised".
Some 1,300 Palestinians, of whom 412 were children, were killed and thousands of homes and businesses destroyed in December and January as Israel tried to bring an end to cross-border rocket attacks by Palestinian militants.
Hamas, which controls Gaza but is regarded by both the US and the EU as a terrorist organisation, was not invited to attend the one-day conference.
Development efforts will remain insufficient, powerless and threatened in the absence of a political settlement
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