Sajjeed Mashah, 27, and his wife Shama Bibi, 24, were beaten by a mob of Muslims after allegations they had destroyed a copy of the Islamic holy book.
It's claimed the accusations against the couple were shouted from mosque loud speakers.
Cardinal Vincent Nichols and the Anglican Bishop of Wakefield, Rt Revd Tony Robinson prayed together at St Anne's Cathedral in Leeds.
The Catholic Bishops' Conference of England and Wales is condemning the actions of the mob and is urging the Pakistan Government to bring the perpetrators to justice and protect the rights of minorities.
Cardinal Nichols said: "This is a horrific and tragic event which sullies the reputation of a great nation. Surely all people of true religious spirit will, in response, turn to God in prayer, seeking forgiveness for the violence and destruction of life, pleading for peace in our troubled world.
"For my part I pray for the repose of the souls of the couple and their unborn child."
Bishop Tony Robinson, Chair of the Archbishop of Canterbury's Pakistan Focus Group and who was in Pakistan in March, said: "The savage attack and murder of these two Christians and their unborn child is unacceptable in any civilised society.
"The Pakistan Government must do more to protect minorities in Pakistan from mob rule and a misuse of the blasphemy laws.
"In this country we hold that freedom of religion is at the core of our tolerant and democratic society. As we look around the world today there are many places where people are not allowed this freedom. We must not take the freedom we have lightly and work to change the attitudes of those who persecute people of another faith."
