This paper deals with the issue of training language teachers at university level into adopting a corpus linguistics approach in their teaching. The aim is to help them use a lexcio-grammatical approach in dealing with lexicon, grammar, phraseology, content in general language and in languages for specific purposes. This paper tackles the issue of training language teachers to relatively advanced levels of skills and competences in theoretical, methodological and technical aspects of corpus linguistics. It will be shown that this is needed in order to allow them to use corpora in the classroom, either in a direct inductive approach, or in an indirect approach for preparing teaching materials.