AbstractTranslation in CLIL? It may seem a contradiction in terms. CLIL means Content and Language Integrated Learning, and is based on the assumption that content is taught through the second/foreign language. No room is left to the learners’ mother tongue, which is either declared off limits or used in very limited cases. So, what is the role of translation in CLIL? Is there any place for it at all? In the past few years, there has been a series of hectic efforts put in by schools and universities to organise CLIL programmes and teacher training courses, and a number of studies have appeared to help with the process. In spite of the wide support that is now being given to the use of the first language in language learning, CLIL proponents tend to neglect the role of translation in content and language learning. Drawing on current research on CLIL, this study sets out to investigate the nature of the contribution that translation makes to language and content learning. The work is grounded on research conducted on empirical data drawn from CLIL courses taught since 2005, inspired by social constructivist pedagogy in a networked learning environment, and a collaborative translation approach.