The 45th Infantry Battalion came into existence during the height of insurgency in Eastern Samar in the early part of 1975. To address the situation, the then PRESIDENT FERDINAND MARCOS directed GENERAL FORTUNATO ABAT, the CGPA to organize and deploy one (1) Infantry Battalion. On July 1977, the 45th Infantry Battalion (Provisional) was activated pursuant to GO Nr 93 H3ID, PA dated 5 July 1977.