Cathedral consists of 49 composed pieces of music: 32 electronic works for the Web; 12 chamber works, some incorporating one or more of the virtual instruments; and 5 orchestral pieces, one of which is for Javanese gamelan orchestra. In addition, there are numerous pieces of incidental web music, sound banks, PitchWeb contributions, and online performances by the Cathedral Band. In all, the music of Cathedral consists of four types: virtual, acoustic, improvised, and interactive.

Virtual music is music written specifically for the website; it exists as either sound files or MIDI files, both of which are streamed to the site and heard in real-time using the Shockwave or QuickTime plugin. The acoustic works are incorporated into the site in a series of live webcasts; these are heard using the RealAudio plugin. Additionally, rooms within the site encourage real-time listener contributions that can be mixed into the performance space.