This paper gives a short overview of the history of the Common European Framework of Reference (CEF) and European Language Portfolio (ELP) and explains their aims and functions. It then provides a summary of the ELP use in Europe and in Spain by showing a pilot study of its implementation carried out at the Schools of Civil Engineering and Architecture in the Polytechnic University of Madrid, as well as including specific data derived from this study. The general results obtained so far have been mixed. Thus, whereas positive effects on the learning process, learning outcome, and learner motivation have been observed, many drawbacks have been likewise encountered by students and teachers, such as the rigidness of the self-assessment descriptors, the difficulty in handling and updating, and the amount of time and work that the implementation of the ELP involves. Finally, in view of these difficulties and drawing from our own experience, some suggestions particularly applicable to our case study are shown (Contains 6 footnotes, 5 figures, and 1 table.)