This paper addresses the concept Vocational didactics and argues that the use of this concept is quite valuable when issues related to vocational education and training is discussed. It is obvious that both the VET and VET-TT research and practitioner arenas are in need of concepts acknowledge by all. Often when researchers and practitioners from different countries listen to each other in conferences or reading papers written by foreign authors about vocational education it leaves the listener or reader confused due to the lack of such concepts. The fact that VET and VET-TT in itself are complex activities increases this demand. This is the reasons why vocational didactic are argued for here. We certainly need concepts acknowledged by all in order to better understand each other. In teacher education in Germany and Scandinavia the concept didactics is frequently used. In those countries, didactics has a broad and wide meaning. It comprices curriculum studies, sociological questions and more specific questions related to assessment and grade setting. In the Anglo-Saxon part of the world, the word didactics has a more narrow meaning similar to methodology in specific learning situations. It is with the broader definition vocational didactics is used here. Vocational didactics has shown to be particularly useful in VET-TT seminars when discussing similarities and differences between subject-oriented and vocational education. Especially when trying to understand why subject- and vocational teachers face huge problem to reach a common understanding when discussing didactic issues in their respective teaching profession. This study indicates that the teachers, in many cases, often unknown even to themselves, have different points of departure regarding the origin of their teaching area. Mostly the similarities between subject-oriented and vocational education are taken for granted and the differences thereby hidden and invisible although it strongly affects their view of the best way to learn. It is clear that at the same time the concept vocational didactics is introduced a boundary emerges between subject-oriented education and vocational education. It has to be noted that this boundary is blurred but nevertheless the two fields develops when the concept is introduced. The area, or sphere of subject-oriented education has a knowledge area as its origin with a cognitive learning theory. This knowledge area steaming from the academic disciplines slowly trickle into the school curriculum. The other sphere is formed by vocational education with an activity area and a guided by constructivist learning theory derived from a field of activity and competencies needed to survive in a profession. Furthermore, this activity arena is always interdisciplinary and problem oriented to its nature strongly affecting the way that the training is carried out. As mentioned, the boundary is blurred between the two fields.Information presented here is gathered partly during seminars in research groups, partly in interviews with key-informants and experienced vocational teachers.The thought that the concept vocational didactic might be fruitful in the VET- TT derives from modern concepts such as "reflective practitioner", "practitioner inquiry", "life long learning", "tacit knowledge" and "master-learning". All those concepts indicate that learning is something more than theoretical issues. These thoughts fit well into constructivist theories about learning and activity theories about learning in a complex context. Such thoughts about the nature of learning break new ways and open up new assumption about what learning really is about. At the same time it challenges the old academic hegemony to decide what knowledge is important but also put a value of this knowledge in the form of academic merits.References will be completed in the paper