The Israeli army said 33 trucks had been let in. The UN refugee agency confirmed an aid delivery, but not the number of truck which had entered.
Gaza has been suffering from shortages and power blackouts since Israel sealed its borders two weeks ago.
Earlier, caretaker PM Ehud Olmert has said Israel will free 250 Palestinians as a "goodwill gesture".
The detainees would be released in advance of the Eid al-Adha Muslim holiday in early December, a spokesman said.
The announcement came as Mr Olmert met Palestinian leader Mahmoud Abbas for their latest round of talks in the troubled peace process.
Israel last freed jailed Palestinians, 198 of them, in August. In all about 11,000 are held in Israeli detention.
The latest move comes as UK Foreign Secretary David Miliband is due to hold talks in the West Bank with Mr Abbas.
The meeting is among a number Mr Miliband is holding with key regional players, including some in Syria and Lebanon.
He is also holding talks with the main contenders for the Israeli premiership, Tzipi Livni and Binyamin Netanyahu.
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