As a profession, teachers, as well as physicians or lawyers, used to be one of the most traditional and identifiable groups in modern Western societies. This paper uses data from an exploratory piece of research to point to the ways in which the educational system's growing deregulation and diversification impinges upon the composition of the professional category of teachers. In the Spanish formal educational system, a particular kind of training programme aimed at young people with a history of school failure is the most deregulated educational modality. This paper offers a description of the sociodemographic and professional profile of teachers in those schemes. The data suggest that this professional group is very heterogeneous, mainly in terms of their working conditions, and that its internal differentiation is linked to emergent educational policies. It concludes that our teachers can be regarded, in the educational field, as an example of a more general process of internal differentiation within semi-professional categories that emerges alongside the growing deregulation and of labour markets and the deterioration of working conditions.