Frontier Corps soldiers were patrolling the double road area in Quetta when unidentified gunmen opened indiscriminate firing on their vehicle.
In the firing, four of the FC soldiers sustained multiple gunshot wounds and died later on their way to hospital, an official said.
Baluchistan Chief Minister Sanaullah Zehri condemned the attack on the security forces and said such terrorist attacks will not deter them from their war against terrorism.
Zehri said the spate of attacks on security forces in the last 48 hours was an attempt to spread fear and panic in the city ahead of the Eid festival.
No group claimed responsibility for the attacks on the FC personnel but there have been several targeted attacks on security personnel including policemen in Quetta and other parts of Baluchistan in last two years.
Mineral-rich Balochistan of which Quetta is the capital has been plagued for decades by separatist insurgency and sectarian killings.