Abstract
The article aims to thoroughly describe the professionality that one can get when two teachers fit in an uncommon school project caused by institutional requirements. The educational perspectives assume that, beyond the specificities of the educational environment, the knowledge to be learned is mediated within and by the relationship between the teachers and the learners, and it turns out to be the main organizer of teaching-learning practices. This clinical didactical longitudinal analysis of dual intervention in a multidisciplinary teaching project in middle school allows to understand how professional teaching skills are acquired in a multidisciplinary teaching environment.