The conception of computational thinking is inconsistent across the world curricula, which is related to the different approaches to implementing its targeted development in schools. The lack of an accepted exact definition has led to a number of problems with the implementation of this way of thinking in the educational process in the Czech environment, and although we are currently moving towards a clearer definition of computational thinking, it is still surrounded by a number of preconceptions. So the question arises, what exactly is computational thinking in the context of primary education in the Czech Republic? How can we diagnose its development and what is the common level of computational thinking in pupils? Finding the answers to these questions is quite crucial for the further development of informatics education in domestic primary schools.