The pledge to investigate the bombing came after talks between the leaders
Pakistan has offered to investigate a bomb attack on India's embassy in Kabul last month that killed more than 50 people, India's foreign secretary says.
The announcement followed talks between the two countries' prime ministers at a South Asian summit in Sri Lanka.
Pakistan has come under pressure over claims, which it denies, that its spy agency was involved in the bombing.
Earlier, the Indian foreign secretary said relations had deteriorated to their worst level for four years.
The leaders are attending the South Asian Association for Regional Co-operation (Saarc) summit in Colombo along with leaders from Bangladesh, Sri Lanka, the Maldives, Bhutan and Nepal.
"(Pakistani) Prime Minister Yousef Raza Gilani said he would conduct an independent investigation," Indian Foreign Secretary Shiv Shankar Menon said.
Mr Gilani met Indian Prime Minister Manmohan Singh on Saturday.
Tensions between Pakistan and India - Saarc's biggest and most powerful members - have been exacerbated by a series of bomb attacks on Indian cities and continued hostilities in the disputed border area of Kashmir.
Tensions between Pakistan and India have overshadowed the summit
India has accused Pakistan of violating a ceasefire accord in Kashmir, and troops from both sides traded gunfire earlier this week.
Addressing the summit, Mr Gilani condemned last month's Kabul embassy attack, in which two senior Indian diplomats died, and some 150 people were injured.
Officials from India and Afghanistan have publicly accused elements in Pakistan's Inter-Services Intelligence (ISI) of involvement in the attack.
On Friday, newspaper reports in the US quoted Washington sources levelling the same accusations against the ISI.
Pakistan's Foreign Ministry issued another denial, describing the claims as "total rubbish".
While food security and trying to improve the lot of the poor are on the agenda at the Colombo summit, correspondents say the key issue is whether the Saarc countries can work together to fight crime and terrorism.
On Saturday, the eight leaders called for a joint effort to combat terrorism.
Afghan President Hamid Karzai told the meeting that terrorism and its sanctuaries were gaining a deeper grip in Pakistan, and called for "collective action to wipe out terrorism in the region".
"While the region has to deal with a myriad of serious problems such as chronic poverty, food and energy shortages, environmental degradation and the like, terrorism is by far the greatest and most menacing of all," he said.
Heavy security is in place for the Colombo conference, with almost 20,000 police and troops deployed to guard delegates as fighting in Sri Lanka's decades-long civil conflict continues.
Tamil Tiger rebels declared a unilateral ceasefire throughout the talks, but the government rejected the truce.
Security has been massively stepped up in Colombo for the summit
There were reports of new military battles in rebel-held areas in the island's north, with the Sri Lankan military saying at least 11 of its soldiers had been killed in fierce fighting.
South Asia is home to the one-fifth of the world's population, but hundreds of millions of South Asians live in poverty.
Since Saarc was founded in 1985, the group's summits have been long on rhetoric but short on follow-up action, analysts say.
The regional grouping has often been overshadowed by tension and hostility between India and Pakistan.