The topic of this diploma paper is the role of a piano accompanist in working with children's choir. During the preparation and practical work on the diploma paper, the author analyzed relevant articles and references dealing with the children's choral compositions with the piano accompaniment. The role of piano accompanist in working with choirs has changed in the course of the history. The piano accompaniment referred to accompanying the pianist himself but also accompanying soloists and choirs. In the time of Schubert, the art of accompanying became the psychological basis to soloists’ interpretation. When it comes to choir accompanying, the character of the contemporary piano accompanist is defined through the relationship with both the conductor and the choir. As a member of a choir organisation, a piano accompanist participates in musical rehearsals by creating a harmonious background to singing practice, by carefully observing music literature and thus facilitating the process of preparing and performing musical pieces. He must have collaborative skills and developed piano playing techniques that are essential in music rehearsals and performances. The purpose of music rehearsals should be the music itself, as well as organizing and conducting music creating processes to a common goal – a successful performance in which the piano accompanist plays an important role as an artist and collaborator.