Bass pedals are an electronic musical instrument with a foot-operated pedal keyboard with a range of one or more octaves. The earliest bass pedals from the 1970s consisted of a pedalboard and analog synthesizer tone generation circuitry packaged together as a unit. The bass pedals are plugged into a bass amplifier or PA system so that their sound can be heard. Since the 1990s, bass pedals are usually MIDI controllers, which have to be connected to a MIDI-compatible computer, electronic synthesizer keyboard, or synth module to produce musical tones. Some 2010s-era bass pedals have both an onboard synth module and a MIDI output.

Bass pedals serve the same function as the pedalboard on a pipe organ or an electric organ, and usually produce sounds in the bass range, which, in organ terminology is the 16′ stop. Some bass pedals have an 8′ stop (an octave higher) which can be used by itself or combined with the 16' stop. Bass pedals are used by keyboard players as an adjunct to their full-range manual keyboards (the keyboards played with the hands), by performers of other instruments (e.g., electric bass or electric guitar), or by themselves. Bass pedal units usually have a smaller range (13 notes) than a church pipe organ's pedal keyboard (32 notes for an American Guild of Organists standard pedalboard). Bass pedals with larger ranges are less common, but do exist, such as 17 notes (C to E), 20 notes (C to G), and 25 notes (C to C two octaves higher). As well, bass pedals usually have shorter pedals than those on a church pipe organ's pedalboard.

All bass pedal units consist of foot-operated pedals mounted in a chassis that sits on the floor. The chassis has buttons on top, also designed to be operated with the feet, which enable the performer to change the sound. Typical buttons include a 16' and 8' button to give a contrabass or bass sound. Some models may have a sustain button; despite the name, it is used differently from an electronic piano's sustain pedal. Whereas an electronic piano's sustain pedal is a momentary, non-latching switch depressed to provide sustain, and then released to end the sustained note, a bass pedal unit's electronic sustain is a latching switch, which, when clicked on automatically sustains all notes for a fixed, short period after the pedal is released. The benefit of the bass pedal's sustain button is that it facilitates legato, sostenuto basslines in slow ballads. Some units with sustain also had a rolling dial to enable the setting of the automatic sustain length.

A 1970s-era bass pedal is typically monophonic, which meant that it could only play one note at a time. Even if the player presses two pedals simultaneously, such as a C and a G, only one note sounds. Given that bass pedals are typically used to play deep-pitched basslines, some models had a "low note priority" circuit. With this circuit, if the player pressed two or more pedals, the unit would only sound the lowest pitched note. A 1970s unit might have a choice of several imitated instruments, such as organ bass, string bass (with more decay), or tuba. Some units had a rolling dial, once again foot-operated, to control the volume. A 1970s unit might have a single output: a 1/4 jack. A unit from this era might have only one visual indicator: a power on LED. Since the bass pedals are on the ground, there is a risk that the player might accidentally press on one of the buttons and change the sound. To reduce this risk, some bass pedals have plastic covers over some of the buttons or U-shaped "switch guard" protectors near some buttons.

Some 1990s and later bass pedals gave the player the option of selecting a monophonic or polyphonic setting. The polyphonic setting could sound more than one pitch at a time. Even though contrabass instruments are less likely to be used to play chords (three or more notes sounded together) than their higher-pitched cousins (as deep-pitched chords can sound unclear and "muddy"), a contrabass instrument like a bass pedal unit can still effectively play some dyads (two-notes sounded together), such as perfect fifths, perfect fourths, and octaves. On a bass pedal unit with a wider range, such as a 20-note unit, a minor tenth or major tenth might sound pleasing, especially at an 8' register.

A 1990s or later unit might have a 1/4 jack output and one or more 5-pin MIDI jacks (e.g., MIDI out or thru). Some 1990s or later units have alphanumeric LED displays and/or small LEDs to provide information to the player about the settings.

A few of the bass pedals designed to be used with electronic or clonewheel organs have features that operate the upper manual keyboards, such as an expression pedal or swell pedal, which is a treadle-style potentiometer for controlling the volume; buttons to turn on or change the speed of a Leslie speaker, a rotating horn speaker in a cabinet; or program change buttons, which send a MIDI message to the other upper keyboards to change to a new sound or setting.

Some bass pedals designed to be used with electronic organs have a MIDI merge feature, so that one or more keyboards can have their MIDI outs plugged into the bass pedal, and then the bass pedal merges the MIDI messages and sends them, via the bass pedal's MIDI out, to the organ sound module. This function might be needed if a keyboardist had two MIDI controller keyboards, and the bass pedals, and wants the MIDI messages from all three controllers to be sent to the sound module.