Abdul Gani killed his daughters 20-year-old Shamim and Noreen and later confessed to the crime upon his arrest, according to DSP Fazal Wahid.
The crime took place in Peshawar's Achar Kali area on September 20.
The accused's son reported the murders to police and lodged an FIR in the case, the officer said.
Police had to conduct several raids before the accused was apprehended from the Mosam Ghari area here, two days after the murders.
According to the DSP, Abdul Gani said he killed his daughters because he was "ashamed at their conduct as they used to leave the house at all hours," the Dawn reported.
The legislation on honour killings introduced tough punishment for convicts, making it stricter than that in usual murder cases.