In general, participants use MOOCs for individual learning purposes by selecting certain contents of a MOOC in which they are interested. Simultaneously, MOOCs are used in the context of online-lectures offered to students who must or may enroll for a specific course to earn credits. However, many participants do not successfully complete all units of a MOOC. Therefore, completion rates —in general— are rather low. Certificates like PDF-documents or electronic badges can be an adequate stimulation to complete a course. This research raises the questions, how the certification of MOOC-participants can be managed and if certificates have an impact on completion rates. Firstly, general aspects of certification are discussed. This is followed by a practical insight into the certification practice based on experiences of the Austrian MOOC-platform iMooX operators. As a conclusion, results are summarized and related challenges and further research questions are addressed.