The military bombed a rebel camp early Wednesday in northern Antioquia state, Defense Minister Juan Carlos Pinzon said.
He said the guerrillas slain included the leader of the 37th Front of the Revolutionary Armed Forces of Colombia, or FARC. The Colombian air force identified him as Luis Enrique Benitez.
Pinzon said no casualties were reported among the army's special forces troops involved in the operation.
The FARC has an estimated 9,000 guerrillas and has been fighting the government for decades.
The guerrillas have continued inflicting casualties in recent ambushes and hit-and-run attacks on security forces. Authorities blame the rebels for two bombings that killed 16 people in provincial towns in February.