Vocalisation has been suggested to be indicative of internal states of an individual in several species. In domestic pigs, vocalisation has been described as part of the stress response, providing a potential indicator of negative emotional states and impaired animal welfare. This thesis focuses on stress-related acoustic communication in the domestic pig. Bioacoustical and ethological, but also physiological and neurophysiological methods are established and/or used in order to provide a holistic view on stress-related vocalisation from the sender to the receiver.