The inclusion of pupils into schools of the main educational stream is emphasized at the international level. Recently, this trend is more strongly applied in post-communist countries, where the now-criticized approaches (based on the exclusion of pupils with mild intellectual disability and behaviour disorders -e.g. ADHD - and their inclusion into special schools) persisted for a long time. Currently, the discussion on appropriate educational approaches which should be applied is now under development. Contemporary tendencies emphasize principles of so-called inquiry-based learning (IBL).