A hands-free device for a mobile telephone which has a telephone transceiving unit for a mobile radio network and in addition a communication device for the wireless transmission of audio and data signals, with a housing (1) in which a communication device forming a wireless communication connection to the communication device of the mobile telephone and electronics for picking up, converting and forwarding and for reproducing audio signals is located, provides for the operation with a mobile telephone without permanent installations or at least without voluminous permanent installations in a motor vehicle due to the fact that the housing (1) is provided with a display (6) which can be activated for displaying data transmitted wirelessly from the mobile telephone, a cable (4, 4') establishing the connection to a power supply is brought out of the housing (1) and an operating unit (15, 32) is provided for operating a mobile telephone via the wireless communication connection.