For a professional user of MT, quality, performance and cost efficiency are critical. It is therefore surprising that only little attention – both in theory and in practice - has been given to the task of post-editing machine translated texts. This paper will focus on this important user aspect and demonstrate that substantial savings in time and effort can be achieved by implementing intelligent automatic tools. Our point of departure is the PaTrans MT-system, developed by CST and used by the Danish translation company Lingtech. An intelligent post-editing facility, Ape, has been developed and added to the system. We will outline and discuss this mechanism and its positive effects on the output. The underlying idea of the intelligent post-editing facility is to exploit the lexical and grammatical knowledge already present in the MT-system’s linguistic components. Conceptually, our approach is general, although its implementation remains system specific. Surveys of post-editor satisfaction and cost-efficiency improvements, as well as a quantitative, benchmark-based evaluation of the effect of Ape demonstrate the success of the approach and encourage further development.