Classic drum and bugle corps are North American musical ensembles that descended from military bugle and drum units returning from World War I and succeeding wars. Traditionally, drum and bugle corps served as signaling units as early as before the American Civil War, with these signaling units having descended in some fashion from ancient drum and fife corps. With the advent of the radio, bugle signaling units became obsolete and surplus equipment was sold to veteran organizations (such as the Veterans of Foreign Wars and American Legion, two major organizers for classic drum corps). These organizations formed drum and bugle corps of civilians and veterans, and the corps performed in community events and local celebrations. Over time, rivalries between corps emerged and the competitive drum and bugle corps circuit evolved.

Traditional drum and bugle corps consist of bell-front brass horns, field drums, a color guard, and an honor guard.

Drum and bugle corps have often been mistaken for marching bands, since there is a similarity to both groups having horns and drums; and they are both essentially bands of musicians that march. The activities are different in organization (marching bands usually associate with high schools and colleges while drum corps are freestanding organizations), competition and performance (marching bands perform in the fall at football games, drum corps usually compete during the summer), and instrumentation (classic drum corps use only brass bugles and drums, marching bands incorporate woodwinds and other alternative instruments).