In this study, we examine how musical play affect the development of musical abilities of first-grade pupils of elementary school. The research consisted of three parts: the initial testing of pupils' musical abilities, holding ten hours of music lessons in which the emphasis was placed on conducting musical play, and the final testing of pupils' musical abilities. With the Mann-Whitney U-test, we found that the difference in the results of the initial and final testing was statistically significant for all three musical abilities -- reproducing rhythmic phrases, reproducing individual tones, and reproducing melodic phrases. In this way, we proved that the musical play that is conducted as part of music teaching contributes to the development of pupils' musical abilities.