This article examines the way in which music has featured in documentary films and programmes. The conventions of restrained use to cue mood and theme are explored, using examples and the recommendations of manuals. Across the varieties of documentary output, the article notes how the dominance of journalistic and observational formats has, for different reasons, tended to place music in the margins. Drawing on an example from the classic period of documentary film-making in Britain, it points towards a more expansive use of music in a complementary relationship with images. A number of general theoretical points about the specific properties of the documentary image and its relationship with music are raised and recent examples of successful innovation discussed. The article ends by suggesting that there is more scope for aesthetic development in music-image relations than has often been recognised and that some of the established inhibitions about mixing ‘fact’ with ‘emotion’ need to be reviewed.