Today's children live in a world where music in all its different forms has become a significant factor in their everyday life. This article describes a 2-year empirical study of nine 8-year-old Swedish children creating music with synthesiser and computer software. The aim of the study is to describe and clarify the creative processes of computer-based composition. The tasks given to the children were framed as invitations to create music to different pictures. Computer MIDI-files were systematically collected covering the sequence of the composition processes step by step: observations were made of their work; and interviews were carried out with each of the participants. In the analysis, five variations of the practise of composing were identified, each with a different object in the foreground of the activity: (i) the synthesiser and computer; (ii) personal fantasies and emotions; (iii) the playing of the instrument; (iv) the music itself; and (v) the task. The findings of the present study also give evidence that young children are able to create music with form and structure.