Music has a strong influence on growing up and maturation of children and presents an integral part since birth in an individual's life. A child has a natural need to express their musical experience completely. By listening and playing music, every child turns on their senses and gets to know them better. By creating music through the so-called Orff instrumentarium, German composer Carl Orff wanted to stimulate a child's creative potential from their first encounter with music. In the desire to enable the whole musical expression to a child, he included different modes in his musical-pedagogical concept like body percussion (clapping, snapping fingers, stomping, playing on different parts of the body, etc.). The use of body percussion as an instrument (clapping, snapping fingers, etc.) is one of the ways to create music within Orff's musical-pedagogical concept. To stimulate the inner sense for rhythm and to provide the opportunity of a unique musical experience in a child, he included instruments as well next to body percussion, especially rhythmic and melodic percussion in so-called Orff intrumentarium that is adjusted to child's age. Along with basic characteristics of Orff instrumentarium and different possibilities of its use (along with adoption/introduction and repeating of a song and rhymes and listening to music) in this paper the Orff instrumentarium is shown as a medium of a child's multimodal expression. With its use, the enrichment of a child's spontaneous synthetic expression comes with a song, dance and pronunciation of rhyme just like during listening to music. The Orff musical therapy described in the middle part of the paper is useful for a therapist to understand a child's needs better. The goal is to stimulate imagination in children, to develop a personality and creativity so they would slowly learn to be their own composers. Orff instrumentarium in the concept of an active and multimodal way of a child's musical expression in early and preschool years is shown in the last part of the paper.