Sharif was scheduled to leave for Britain today but he cancelled his trip after the blast last evening at Gulshan-e- Iqbal Park in Lahore where Christians were celebrating Easter, a spokesman at the prime minister's secretariat said.
Sharif was to meet British prime minister David Cameron and then fly to the US for the Nuclear Security Summit 2016.
"He will now travel directly to the US after a couple of days," the spokesman was quoted as saying by The News International.
In the wake of the attack, the Punjab government had declared an emergency in Lahore and announced three days of mourning.
The brutal attack killed over 70 people and was claimed by the Jamaatul Ahrar, a splinter group of the Tehreek -i-Taliban Pakistan (TTP), which released a statement saying it targeted the Christian community on the occasion of Easter and warned of more such attacks.
Jamaatul Ahrar had also claimed last year's twin suicide bombings at churches in Lahore's Youhanabad area, which killed at least 15 people and sparked violent protests across the city.