In this chapter, we present results on the impact of professional experience on the task of post-editing. These results are part of a larger research project where 24 translators and three reviewers were tested to obtain productivity, words per minute, and quality data, errors in final target texts, in the post-editing of machine translation (MT) and fuzzy match segments (in the 85 to 94 range). We will discuss here the results on the participants’ experience according to their responses in a post-assignment questionnaire and explain how they were grouped into different clusters in order to correlate firstly the experience with speed according to the words per minute in the different match categories: Fuzzy matches, MT matches (MT output) and No match and secondly, to correlate them with the quality provided by measuring the errors marked by the three reviewers in each match category. Finally, conclusions will be drawn in relation to the experience and the resulting speed and number of errors.