Sufis, a minority Muslim group who follow mystical beliefs, are regarded as heretical by hardliners.
A Taliban fighter told reporters his group carried out the attack, the third on Sufi shrines in a year.
Ehsanullah Ehsan told Reuters news agency the attack was in revenge for a government offensive against militants in Pakistan's north-west.
Sunday's blasts hit near a shrine to Sufi saint Sakhi Sarwar in Dera Ghazi Khan district, and devotees were reportedly among the dead and wounded.
"We have recovered 41 bodies so far," police officer Zahid Hussain Shah told AFP news agency.
- July 2010: 42 killed in suicide attack on Lahore Sufi shrine
- May 2010: 93 people killed in attacks on two Ahmadi mosques in Lahore
- Jan 2010: A bomb at a volleyball match kills about 100
- Oct 2009: At least 120 die in car bomb attack on packed market in Peshawar
He said both explosions had been caused by suicide attackers, adding: "They came on foot and blew themselves up when police on duty stopped them."Another police officer told reporters that a third attacker had been caught before he could detonate his explosives
Eyewitness Faisal Iqbal told Reuters he had been standing yards away from one of the explosions.
"People started running outside the shrine. Women and children were crying and screaming. It was like hell," he said.
Thousands of people had been marking the annual festival of Urs at the time of the blasts.
Sufism has been widely practised in Pakistan for hundreds of years - analysts saying it has a much bigger following than the hard-line Taliban version of Islam.
Devotees perform singing and dancing and pray to saints who are honoured with numerous shrines.
Their beliefs are considered un-Islamic by hardliners, who have targeted their shrines several times.
Last October, a suicide bombing at a shrine in Punjab province left six people dead.
And earlier in the year a suicide attack on a Lahore shrine killed at least 42 people, making it the most deadly such attack on record.
For decades, the government has also sought to suppress Sufism, and has put it under strict control.