''This is a great victory for the United States and the international community as a whole in the struggle against Al Qaeda and terrorism. Frattini said in a statement.
The US announced the killing of Bin Laden by US special forces in a "firefight" on his sprawling fortified compound in Abottabad about 100 kilometres northeast of Islamabad.
US officials said Bin Laden was shot in the head after offering resistance during the raid, which lasted around 40 minutes. One of Bin Laden's sons, two couriers and a woman was killed in the operation, according to the officials.
The US said it had DNA evidence to prove it had killed Bin Laden and said his body had been buried at sea.
Frattini praised Washington for the operation. "It was a victory made possible by the determination of the United States to go after those who were responsible for the most tragic event of the start of the present century, the '9/11' attacks and numerous other massacres," he said.
Bin Laden, as head of Al-Qaeda's operations was the suspected mastermind of the 11 September 2001 attacks on US cities which left 3,000 people dead, amongst a string of other international terrorist attacks.
"It was victory of good over evil, of justice against wickedness, of the free and democratic world, " he said, while warning countries not to lower their guard in the battle against terrorism.
Internationation terrorism had not been defeated "but it has certainly been weakened in the world," said Frattini.
The next target would be the Afghan Taliban's reclusive leader Mullah Omar, he added.
Earlier, US president Barack Obama said it was "the most significant achievement to date in our nation's effort to defeat Al-Qaeda".
International terrorism had not been defeated "but it has certainly been weakened in the world," said Frattini, adding that the next target would be the Afghan Taliban's reclusive leader Mullah Omar.
Afghan president Hamid Karzai said Bin Laden had "paid for his actions".