Officials said gunmen riding a motorcycle fired indiscriminately at a police patrol near Khattako Pul, a suburb of Peshawar.
A policeman was killed instantly and the attackers fled after the shooting.
Additional policemen rushed to the spot and cordoned off the area before launching a search operation.
Attacks on policemen by suspected militants have increased in the past few weeks. No group claimed responsibility for today's attack though such incidents are blamed on the Pakistani Taliban.