This article describes the music data format of the recently introduced Sound Notation system, and how it makes possible computer-aided composition of scores represent- ing sound-based music. The Sound Notation system is an adaptation of Lasse Thoresen’s spectromorphological analysis notation, developed for composition and analysis. A detailed description of the data format is followed by two examples of its application in a computer-aided composi- tion process resulting in the sounding interpretation of two score excerpts of an electroacoustic composition. Generat- ing sound structures as symbolic notation data in this way provided possibilities for the creation of sound-based mu- sic otherwise limited to works of traditional notation.