The organisers of the event said that an official of the Guinness Book of World Records was present and watched the gathering, including athletes and students, as it sang the anthem this evening.
Punjab Chief Minister Shahbaz Sharif, whose government played a key role in helping organise the event, joined the crowd. So did several artists including singer and actor Ali Zafar.
The event was the main feature of the Punjab Youth Festival 2012 in which students and athletes from institutions from across Punjab participated.
Several rehearsals were conducted before the record- breaking attempt.
"I have seen very few events like this one in the city of Lahore. Events such as this prove the resilience of the Pakistani people," Sharif said.
The coordinator to the Youth Festival, Rana Mashhud, told reporters that the world record was earlier held by a crowd of 21,000 people.
"We have registered a new record with some 70,000 people, including athletes and students, taking part in singing the anthem," he said.
The arrangements made for the event had met the specifications laid down by the Guinness Book of World Records, Mashhud said.