The purpose with the essay was to describe and judge if ABA was as good method for working with behaviourproblems in children within childcare and school. The study gave knowledge about behaviourtheraphy and the behaviourists through history, facts about ABA, that was the method I used. The study was based on participational observations. Three choosen pupils with diffrent behaviourproblems was observed and analysed according to ABA. To sum up the result of the study pointed at ABA to be a well-functioned analysing method to determine the typ and sort of the behaviorproblem. As a workingmethod for behaviourproblems ABA was well-funvtioned in simpler behaviorproblems, but needs to be completed in more difficult behaviorproblems with more underlying factors.