While language teacher education programmes and language syllabi in secondary education encourage the use of the target language in the classroom, resources to support teachers in this endeavour, such as books with useful phrases, do not state that the examples they provide are corpus-based, i.e. drawn from actual language use rather than invented phrases. This paper investigates whether consultation of a corpus of classroom discourse can be of benefit in language teacher education. The paper describes a project involving the creation of corpora of classroom discourse in French and Spanish, and the use of these corpora with student teachers. After setting the research in the context of corpora and classroom interaction, it examines issues such as the content of the corpora, the type of consultation (direct or mediated by the teacher), and the student teachers' evaluation of the activity. Special attention is paid to one particular aspect of classroom interaction, discourse markers.