The remote control of an operational parameter, such as the amplification factor (A) of the amplifier (19), of a hearing aid (1) occurs via a control signal in the form of acoustic waves (11) transmitted by a transmitter (10) of a remote control unit (2) and received by a pick-up (15) of the hearing aid (1). The acoustic waves can be ultrasonic waves or modulated waves and make it possible to reduce the size of the hearing aid, resulting in a more compact device that can easily be controlled remotely, for example, by means of a manually adjustable volume control located in the remote control unit.