An electronic musical instrument capable of providing automatic bass and chord accompaniments, either in accordance with a program prepared by the player or in immediate response to the depressing of a minimum number of keys on lower and pedal keyboards. The programmed accompaniments proceed sequentially (in steps) with successive measures of accompaniment data being read from a memory. By making some of these measures blank in introducing the accompaniment data into the memory, therefore, the player can play desired bass and chord accompaniments by direct key depression during the blank measures. In an alternative embodiment the production of the programmed accompaniments is automatically inhibited during the production of key-responsive accompaniments, thereby enabling the player to override the programmed accompaniments at any time.