In my investigation I concentrate specifically on cases of children from three children{\crq}s homes in Italy and Czech republic (Casa del bambino PIO XII., private children{\crq}s home Marketa and Church children{\crq}s home Emanuel). In these homes they use preventative bahaviour system founded by Don Giovanni Bosco who was the Italian priest and educator who lived in the 19 century and he founded the work which was dedicated to the poor young people without their home in Turin.The intention of Don Giovanni Bosco was to help to give the right direction to young people.This system has three basic pillars which are reason, kidness and religion. His system demands from the educator constant presence with the children and education with the example of yourself.The preventative behaviour system of Salesiani and its tradition is worth attention for the the prevention of social {--} pathological phenomena.