Three months after Israel closed it, more than 1500 people used the crossing between Gaza and Egypt, after being cleared by Palestinian officials supervised by EU personnel.
The new arrangements are part of a US-brokered agreement between the Palestinians and Israel which controlled the border until its pullout from Gaza in September.
Opening initially for four hours a day, Palestinian officials expect to process about 600 people a day.
They plan to operate around the clock once all 70 EU monitors are in place.
EU representative Mark Otter declared himself happy with the operation on the first day, and told the Palestinians that their taking control of the crossing was symbolically significant.
"You are slowly acquiring all the prerogative of your sovereignty, of your future Palestinian state and your freedom that you deserve," he said.
The UN Secretary General, Kofi Annan, has congragulated the Palestinians.