Through the present article I will attempt to unveil how the phenomenon indeterminate music is, how it works and how it behaves. I will also try to show how the problems in communication, arising from this kind of music, are and how they manifest. Thus, from a correlational study of indeterminate music, which conceives it as comprised of dependent variables, I will portray the phenomenon of indeterminate music as a communication system constituted by determinate components. To achieve these objectives, I will approach the indeterminate music work from the concrete (by using examples from the repertoire of this type of music) to the abstract (the work as something ideal and general), I will define the components of the phenomenon of indeterminate music and reveal its functioning through a systematic analysis, I will give answers to the problems originating from the phenomenon of indeterminate music through a prediction analysis, and represent the phenomenon of indeterminate music with a model which will show its structure, functioning and use of chance in relation to its communication goals.