US President Barack Obama has urged Pakistan to investigate the suspected network that sustained Bin Laden.
Mr Obama said it had to find out if any officials knew of his whereabouts.
In a statement to MPs about the raid by US special forces which led to the death of Bin Laden last week, Mr Gilani said Lt-Gen Javed Iqbal would lead the investigation into the failures to detect the al-Qaeda leader.
"We are determined to get to the bottom of how, when and why about OBL's presence in Abbottabad," Mr Gilani said.
He mounted a strong defence of Pakistan's record in fighting terrorism, highlighting the "price paid" in civilian and military losses, and the numbers of al-Qaeda militants killed or arrested.
AnalysisMr Gilani's support for the military and the ISI was especially significant, given that both have come under national and international criticism.
But it is also understandable as Pakistan's political elite remains heavily dependent on the army.
Mr Gilani leads a weak coalition government which could have the rug pulled from under its feet if it is perceived to move against Pakistan's national interest.
Mr Gilani's speech may lessen the anger directed by the Pakistani public towards the army.
But it does not succeed in answering many questions - particularly how Bin Laden was able to live in Abbottabad without the knowledge of the country's intelligence agencies.
He said the US raid was "a violation of sovereignty", and suggested that Washington had helped create al-Qaeda during the Soviet invasion of Afghanistan.
The US had then widely dispersed al-Qaeda's fighters by following a "flawed" military strategy to try to capture Bin Laden in the mountains of Tora Bora in 2001, he added.
"We did not invite al-Qaeda to Pakistan," he insisted, saying that the failure to find Bin Laden for 10 years was the result of "an intelligence failure... of all the intelligence agencies of the world" and that "blame games serve no purpose".
He added: "The al-Qaeda chief, along with other al-Qaeda operators, had managed to elude global intelligence agencies for a long time. He was constantly being tracked, not only by the ISI but also by other intelligence agencies.
"It was the ISI that passed leads to the CIA that enabled the US intelligence to use superior technological assets and focus on the area in which Osama Bin Laden was eventually found."Continued