The couple was arrested in July 2013 after an imam alleged they had sent a text message that he regarded as insulting to the Prophet Muhammad.
A defense lawyer for the couple said they denied being responsible for the message.
Lawyer Nadeem Hassan told the AFP news agency that the text originated from a phone that the couple had lost some time before the incident.
Pakistan has extremely strict laws against defaming Islam, and the death penalty can be imposed for insulting the Prophet Muhammad.
Rights activists say the laws are sometimes abused as a weapon in personal disputes.
Based on reporting by AFP and dpa