In 1996, Danish Broadcast Corporation (DR) introduced music controlling software in order to index, plan and program music for their public service popular music radio channel P3. This dissertation is an ethnographic investigation of the work practices around this software asking questions about agency and networks, technologies, music and gender in the daily practices making up the music forP3. Mirroring an ANT (Actor Network Theory) heterogeneous world view the dissertation suggest that the practice of programming and presenting music for contemporary public service youth radio is to be seen as complex processes involving mesh works of humans, things, politics, corporations and technologies of all kinds. Inspired by different post-ANT and STS’s (Science and Technology Studies) theories of algorithms and politics of circulation of culture, the dissertation discuss questions about the use of digital technology in work practices of contemporary public service music radio production.The dissertation furthermore investigates questions of agency and processes of learning in the everyday life of the music radio professionals. It investigates the relation between music and the role of the individual actor in the social. It looks at the position of the subject, of gendering in work environments, of acting and of agency in the everyday work practices on P3 in times of globalconnections, of new digital technologies and of heterogeneity in cultural circulation.The dissertation can be seen as an ethnomusicological contribution to research on radio as well as acontribution to ethnographic research in contemporary institutions and production cultures.