104th Infantry Regiment, was a unit of Philippine Commonwealth Army activated and organized while the war progressed.

It was organized with moros and local recruits within Cotabato-Davao Sector under 101st Infantry Division under Brigadier General Joseph Vachon in Mindanao Island during World War II.

[1] In January 1942, due to sudden influx of volunteers and Moros who wanted to fight the Japanese in Cotabato-Davao Sector General Vachon organized a regiment to control this volunteers and warriors who did not go through a formal training but has a great fighting skills, under American officers.

Colonel Howard Perry then commander of Digos Subsector, allowed a Moro battalion under Captain Henry Macner to fought Japanese in a guerilla warfare resorting to ambuscades and raids to Japanese units.

[2] Due to this success, succeeding commanders Colonel Reed Graves and John McGee expanded this unit to a regiment adding another battalion and deployed in Cotabato subsector under Lieutenant Colonel Russell J.