Writing the script for a documentary film can be problematic. According t some documentary filmmakers, it is not possible at all, because one cannot know beforehand what is going to happen. Nonetheless, a written script is often required to obtain financing for a documentary project. This article deals with different work practices and forms of documentary script. It analyses two case studies: the writer’s own films A Man from the Congo River (2010) and Kusum (2000). The first is the story of an engineer who worked in colonial Congo at the beginning of the twentieth century. It is based on diaries and other historical material, and therefore it was possible to construct a very precise script for the film. Kusum is an observational documentary film following the healing of a young Indian girl. The script was produced prior to production, but during the shooting process many core elements changed, including the main character and storyline. The form and dramaturgy of documentary films are created in the filmmaking process and in dialogue between the filmmaker and real people. A documentary script can be considered a hypothesis about the reality that the filmmaker will encounter via the process of filmmaking. Instead of ‘a screen idea’ we could speak about ‘a documentary idea’.