The world all around us is rapidly developing. We are witnessing the rapid evolution of technology and communication. This means new challenges and responsibilities to future strategies and attitudes. Today's operating systems and development environments apply the principle of OOP; therefore today's developments are inconceivable without the usage of OOP. The knowledge and usage of OOP and the related system development methods are essential mainly for experienced programmers and developers. Consequently, teaching computer science and programming needs to be based on OOP. OOP can be avoided in case of teaching basic computer skills; however, it is an essential part of teaching programming. It is generally known--based on teaching experiences--that teaching traditional sequential programming is facing difficulties, moreover, teaching OOP, that is closer to reality, is even more difficult. The reason for its difficulty is the fact that further theoretical and modelling skills would be required, but the traditional sequential programming principles should be taught as well. So we can ask when it is appropriate to start the OOP education at schools. Let´s take into consideration that to be able to learn programming, algorithmic thinking is essential. It raises further question such as: what method to use for teaching, how to teach students the most effectively and in the shortest period to be able to use this technique.