Several developments during the last decades have provoked spectacular changes in both Mathematics Teaching and the Education of Mathematics Teachers. From this perspective of renovation, we wish to define a new context in mathematics teacher education in which we consider that "pedagogical content knowledge" (Shulman, 1993, Mellado, 1998; Blanco & Otano, 1999) has to be the knowledge base for the education of the future teachers. In the present work, using problem solving as reference, we explain our program and different types of activities which help to create learning environments referred to "learning to teach mathematics". These activities allow the prospective teachers to build up their own pedagogical content knowledge. (Contains 2 figures.)