||This paper’s aim is to analyze teachers` code-switching from L1 (Italian) to L2 (English) in various CLIL contexts in Italy. For years the shift from L1 to L2 was banned in language classes since it was thought that in this way the learning of the foreign language could be impaired. On the contrary, in recent years there has instead been a recognition of the validity of code-switching which has been considered as a strategy adopted by all bilingual speakers (Baker 1996, Butzkamm 1998, Cook 2001, Franklin 2001, Gajo 2001, Ricci Garotti 2006, Myers 2006, Bentley 2008). Therefore, if CLIL, as it is, is to be assimilated to bilingual learning then code-switching should be present in CLIL contexts. We aim at answering the following research questions by means of a qualitative research method: when does code-switching in teacher’s speech occur and what is its role? What differences are there between first, middle and secondary teaching with regards to code-switching by the teacher? To test this, three different types of schools have been chosen to be analysed, primary, middle and secondary. Almost six hours of teaching have been audiorecorded by means of a digital recorder with a microphone connected only to the teacher. Therefore examples of code-switching in the teacher’s talk have been gathered. The students couldn`t be recorded for privacy reasons. Secondly, the researcher has filled in an observational grid on the basis of Bentley`s categories in order to see in what types of activities code-switching does occur with regards to both teachers and learners. Thirdly, a questionnaire has been filled out by the teachers in order to compare the field notes with their perceptions of the use of code-switching. In general, not many differences have been found out in the use of teacher’s code-switching for primary, middle or secondary school. Nevertheless, the study has shown that according to what could be expected, the primary school teacher makes an extensive use of code-switching. The middle school teacher also uses it a lot even for non didactic activities such as reproaching the students. The high school teacher, on the contrary uses it very rarely and only for guiding or instructing the students. All of the teachers observed used code-switching for eliciting the switch as a natural activity to be developed in bilinguals and also to explain the lexis. This seems to be very useful especially for younger students in order to give them the lexis in both languages. The risk here, especially with specific lexis, is that the children learn the foreign word but they never have the chance to know the term in their native language. As regards the teachers` opinions on code-switching, all of them are in favour of it. They are very aware of their use of it but less of the use of it by the students. That is to say they think they allow it less than they actually do. To sum up, according to Baker (1996) all teachers use code-switching for didactic and non didactics functions but give less attention to the type of skill where they use it. According to Gajo`s (2001) categories they all use micro alternance more than macro alternance. This is supposed be very positive because it is the real bilingual skill.