In the past decades much research has been performed to investigate the influence of music practice on cognitive performance. However, most of these studies have been performed in laboratory settings or in relative small experiments.The present cross-sectional survey investigates the correlation between musical practice during childhood and cognitive performance in a large sample. Primary schools (N=33) co-operated in this study and 860 students received the questionnaire (appendix 1). The parents of these students were asked to complete the questionnaire (appendix 2). Within two weeks 366 questionnaires were returned. The response rate is 44.6%. Cognitive performance was measured with the CITO-eindtoets-score (a national assessment for final year primary school students).Extra-curricular practice of music during the time of primary school led to a significant higher CITO-eindtoets-score for the students that had musical training during the time of primary school (p = .002). After adding socio-economic status to the model the effect of musical practice on CITO-eindtoets-score was still significant (p = .023). There was on interaction of musical practice and socioeconomic status. Jan KnoorenThe influence of music practice during primary school on congitive performance 169