The Civil Engineering Course of the University of Minho in Portugal started with peer assessment in the first year of the academic year 2004/05. The implementation of peer assessment at this course was a consequence of the successful mplementation of peer and self assessment at other engineering courses of the University of Minho. This article will outline the motives for the implementation of peer assessment, the expected and obtained effects and will delineate the group work processes that are put into action at the first year of the Civil Engineering Course. During the semester, three assessment moments take place in two subjects, with a different assessment task at each moment. Students are supposed to assess the work of the peers, supported by well defined criteria that are partly the results of a negotiation process between students and teacher. They subsequently mark the work of their colleagues and provide a clear justification for each given mark. The aim of this method is to involve them in the subject, enhance their motivation and in that way deepen their learning. Advantages and disadvantages of peer assessment from both the teacher’s and the students´ perspective are discussed. The results that have been obtained so far, point at a successful implementation of peer assessment. The implementation process relied on strong institutional and pedagogical support, that were considered crucial to the changes that were realized