One Frontier Corps personnel was martyred while another was injured in an improvised explosive device (IED) blast in the Sarokai district of South Waziristan on Monday, official said.
According to a political administration official in the area, the soldiers were on routine patrol when a hidden IED exploded near the Gurguray checkpost in Sarokai.
Security forces have cordoned off the area.
South Waziristan is one of the seven semi-autonomous tribal areas, where the army has for more than a decade been battling militants linked to the Taliban and Al-Qaeda.
The army launched an operation in June 2014 in neighbouring North Waziristan to wipe out militant bases in the tribal areas and end an insurgency that has cost thousands of civilian lives since 2004.
As a result security has improved. Attacks still take place but fewer than previously.