A device for non-invasive ultrasound treatment of disc disease. This device includes a therapeutic ultrasound transducer which is provided for treatment of the disc, preferably nucleus pulposus, of a patient by generating an ultrasonic field, the temperature focus (F) of which is located in the disc, preferably nucleus pulposus, for heating thereof. The therapeutic ultrasound transducer is of a "phased array"-type and a diagnostic ultrasound transducer is provided to determine the acoustic properties of the patient's tissue. An optical navigating device including at least one diagnostic camera and at least one signal receiving and/or signal sending unit is adapted to send or transmit signals to and/or receive reflected or other signals from position transmitters on a reference device and on the therapeutic ultrasound transducer. A computer is provided with at least one computer program which is designed for calculations in connection with settings of the device.