Two suicide bombers struck the famous Sakhi Sarwar Darbar near Dera Ghazi Khan on Sunday while thousands of people were attending the annual `urs` or festival of the 13th century shrine.
Forty-one people were killed yesterday and the others died later, officials said.
Over 100 people were injured in the attack, the latest in a series of terrorist assaults targeting Sufi shrines.
The Tehreek-e-Taliban claimed responsibility for the attack, saying it was carried out in retaliation for military operations against militants in the country`s northwest.
Police officials said their investigations had revealed that the attack was planned in the restive Bajaur tribal region.
Police arrested three terrorists, including two who were described by officials as would-be suicide bombers.
One teenage would-be suicide bomber was shot and injured by police after he lobbed a grenade. Officials said the teenager had told them that he would try to carry out a suicide attack as soon as he recovered.
Officials said the suicide bombers arrived in the Dera Ghazi Khan region four days before the attack.
They had planned to strike the shrine on Friday, when people visit in greater numbers, but were unable to do so.
The Sakhi Sarwar shrine, cordoned off following yesterday`s attack, was reopened to the public today after extensive security arrangements were put in place.
Shops and markets in the area remained closed today as a mark of protest.
The Taliban consider the practice of visiting and praying at Sufi shrines as "un-Islamic" and have targeted shrines across Pakistan over the past few years.
Scores have died in suicide attacks on Sufi shrines, including Data Darbar in Lahore, the shrine of Baba Farid at Pakpattan and the shrine of Abdullah Shah Ghazi in Karachi.