The army on Friday defused an explosive device weighing around 50 kilograms on the outskirts of the town of Arsal, an army statement said.
The bomb was discovered as an army unit was conducting an inspection patrol in the Arsal area of Ras Al-Sarj, according to the statement.
The 50-kilo explosive device was placed in a garbage dumpster and was set for remote detonation.
The patrol immediately cordoned off the location and a military expert arrived and defused it as Military Police launched a probe into the incident, the army statement added.
On Wednesday, a patrol for the army intelligence found three bags containing 66 kilograms of chemicals that can be used for making bombs in the Arsal area of Ain Al-Shaab.
Militants from the Islamic State group and Al-Qaeda-linked Al-Nusra Front overran Arsal last month and engaged in heavy battles with the army.
The fighters withdrew to Syria but took with them hostages from the military and the Internal security Forces. They have beheaded three of them.
Arsal's outskirts are still witnessing sporadic clashes between the army and the gunmen.
Lebanon has seen a string of deadly car bomb attacks linked to Syria's war, most of which were claimed by Syria-based extremist groups.