The War Pipes features a bladder made of leather that is inflated through a pipe by the breath of the musician. The inflated bag is held under the arm and pressed with the elbow to force air through several reeded pipes that are attached to the bag. The musician plays by alternately covering the various holes on one of the pipes, called the chanter, producing the melody. The remaining pipes are drones, each tuned to a single note, that provide a continuous background tone. Bagpipes were used mostly in armies to provide marching music.

Uilleann Pipes In Ireland the war pipes were gradually supplanted by the Uilleann (pronounced "illyun") pipes, which were invented sometime in the 16th century. This instrument is smaller and quieter than the war pipes, with a greater range: two octaves, as opposed to one for the war pipes. Uilleann pipes are not blown; instead, air is provided to the bag by means of a bellows that is held under the opposite arm and is worked with the elbow (hence the name Uilleann, or "elbow", pipes). A neat little animated image that shows a piper playing can be seen on the Ceol Rince web site, which also provides some pipe tunes in midi format.

A full modern set of Uilleann pipes has seven reeded pipes: the chanter, with its two octave range; bass, baritone, and tenor drones that can be turned on or off at need; and three regulators, which are chanters fitted with keys like those on a flute, and can be used to produce various chords. The Uilleann pipes are the most complex and versatile of all the bagpipes.