Mohammad Shafi, 45, and Mohammad Aslam, 20, were accused of tearing down and trampling a poster of a gathering to mark the birthday of the Prophet Mohammed. They were arrested last April for the offense that happened outside a grocery store.
The judge in the court at Dera Ghazi Khan in the eastern part of the Punjab also fined them each the equivalent of $2,700.
The sentences come after Punjab Provincial governor Salman Taseer, 64, was assassinated allegedly by one of his bodyguards who claimed he shot Taseer because of his public remarks against the blasphemy laws.
Taseer was getting into his car in the fashionable Koshar Market in Islamabad in the early afternoon when he was shot several times at point-blank range.
The veteran politician's death focused public attention on the blasphemy laws that dictate harsh sentences for transgressors. Nearly 97 percent of Pakistan's 175 million people are Muslim while less than 2 percent -- fewer than 3 million -- are Christian.
Religious tensions have been rising in Pakistan in the past several years and resulted in Muslim extremist groups openly attacking Christians.
In July, two Christian brothers accused of writing a pamphlet critical of the Prophet Mohammed were killed as they left a courthouse under armed police guard in Faisalabad.
Opposition parties have expressed concern that the government hasn't indicated it will reform the laws.
Many public rallies have taken place in the past year, organized by Muslim clerics, in support of the laws and against any reforms of them.
Taseer, who championed reforming the laws that in some cases specify death for blasphemers, supported a Christian woman awaiting execution for blasphemy. Asia Bibi was sentenced to hang in public for allegedly insulting the Prophet Mohammed during an argument with other farmhands in a Punjab village in June 2009.
Bibi, 45, is an illiterate farm worker in the Punjab, is married to another laborer and they have five children. She is the first woman to be sentenced to death under the blasphemy law but no date for execution has been set.
Pakistani President Asif Ali Zardari can pardon Bibi. But he ordered a review of the case after an international outcry -- including from the pope -- over the death sentence.
Arif Gurmani, defense counsel for the convicted father and son blasphemers, said he would take the case to the high court because "it has been given in haste" and was the result of inter-faith rivalries.
"Both are Muslim. The case is the result of differences between Deobandi and Barelvi sects," he said. The accuser, Haji Phool Muhammad, belongs to the Barelvi sect while Shafi and Aslam belong to the Deobandi sect.
"Shafi is a practicing Muslim, he is the imam of a mosque and he had recently returned from a pilgrimage to Saudi Arabia … I am defending them because I am convinced they are not guilty of blasphemy," he said.
However, Haji Phool Muhammad told The Express Tribune newspaper that he thought the two should have been given death sentences.
Chairman of the Pakistan Peoples Party, Bilawal Bhutto Zardari, vowed to defend all vulnerable sections of society.
"To those who dare attack my religion, especially those who corrupt its peaceful message, are what I call covert culprits and you will be defeated," he said at a meeting in the Pakistani High Commission -- embassy -- in London.
"This shall be our jihad. Jihad against those who use our religion as a tool to justify their violence, suicide attacks and mass murder. They believe erroneously that their crimes will take them to heaven."
The death of Taseer, a veteran member of the Pakistan Peoples Party, follows that of Bilawal's mother, former Prime Minister Benazir Bhutto, and leader of the PPP. She was killed in a suicide attack when leaving an election rally in the city of Rawalpindi in December 2007.