This paper presents the results of a pedagogical experiment on the development of media literacy in children of primary school age (7-10 years) in different conditions: at home, at home and school, only at school. Parents who took part in the programme "Media Literacy for parents" were involved in this study. The purpose of the paper was to analyse the effectiveness of media literacy tools in primary school children used in different conditions. The study was conducted through a mixed method, using a questionnaire on media literacy and interviews with parents. The level of media literacy development of younger schoolchildren in the group where the techniques were used at home and school is statistically higher than in children from the group where the techniques were used only at school. The interview results confirmed the need for recommendations for parents and the effectiveness of parental mediation in the development of their children's media literacy.