It is generally agreed that all professional translators are now involved in some kind of translator-computer interaction (TCI). This paper investigates the relationship between machines and humans in the field of translation, analysing a CAT process in which machine-translation (MT) technology was integrated into a translation-memory (TM) suite. After a review of empirical research into the impact of CAT tools on translation processes, the authors report on an observational study of TCI processes in one particular instance of MT-assisted TM translation in a major Danish translation service provider. Results indicate that the CAT tool played a central role in the translation process. The translator’s processes are both restrained and aided by the tool. The study shows that the translator resists the influence of the tool by interrupting the usual segment-by-segment method encouraged by translation technology. The study also indicates that the tool helps the translator conform to project and customer requirements.