‘Performing the Posthuman’ is an investigation into reinvented representations, or re-presentations, of body–voice relationships in (musical) theatrical performances that can be called posthuman. Performance analyses lay bare the ways in which these body–voice relationships are used as strategies to theatrically image a posthuman condition. Combining new theories on posthumanism, new materialism and recent findings on the construction of voice, the study’s research dives into the ways in which both, the voice and the body, can be treated as floating signifiers in a mutual and mutable relationship. A close examination of the different ways in which what is posthuman is performed, exposes recurring tensions between modes of representation and presentation on stage.