This dissertation will focus on a fascinating and challenging field of translation: documentary subtitling. For this purpose, the third episode from the BBC educational series "The Human Brain" was selected, transcribed, translated properly and subtitled into Italian at the School of Languages and Area Study of the University of Portsmouth. The discussion is divided into three main sections. The first provides a detailed account of subtitling practice; this is considered necessary in order to better understand the consequent translation choices adopted in the actual process of subtitling. More specifically, subtitling is defined as a particular mode of transfer involving three activities: the transfer from one language to another, the condensation of the on-screen discourse and the transfer from the oral to the written. The second section goes into the specificities of the documentary genre. Following a discussion regarding factual translation and the informative genre documentaries belong to, it examines the textual features of the documentary under study along with its genre-related issues. The documentary is therefore analyzed in detail in terms of topic, format, register and function. Lastly, the third section shows the results that emerged from the process of subtitling "The Human Brain". The adaptations occur at lexico-syntactic level and imply some stylistic and semantic modifications. Such adaptations are examined through several indicative examples, in the light of the translation theories that underpin them. A series of conclusions can be drawn from this dissertation. First of all, documentary translation needs to be looked at from an interdisciplinary approach, which could take into account the various dynamics involved in the semiotic construction of the film. Secondly, although documentaries can be placed within the informative genre, the latter is by no means a fixed entity but it is rather open to cross-generic instances. Knowledge of genre is certainly helpful in setting priorities in the process of translation, but this does not prevent us from considering each documentary as a separate micro-universe. Finally, the inevitable modifications occurring in the target text are not random but based on a process of careful selection made by the subtitler. Given this process of interpretation and rewriting, the subtitler plays an active role in the definition of the final target product.