The use of a low-pitched keyboard or pedal keyboard to substitute for the bass guitar or double bass in music.

The earliest keyboard bass instrument was the 1960 Fender Rhodes piano bass (pictured). It was essentially an electric piano containing the same pitch range as the electric bass (or the double bass), which could be used to perform bass lines. It could be placed on top of a piano or organ, or mounted on a stand. Keyboard players such as the Doors' Ray Manzarek placed his Fender Rhodes piano bass on top of his Vox Continental or Gibson G-101 organ to play bass lines.

About the same time, Hohner introduced a purely electronic bass keyboard, the Basset, which had a 2-octave keyboard and rudimentary controls allowing a choice of tuba or string bass sounds.