This article offers an ecocritical reading of four dystopian films, two from the early 1970s and two from the late 1990s: Silent Running, Soylent Green, eXistenZ, and Gattaca. In particular, it interprets these films – which variously predict the probable ramifications of environmental catastrophe and biotechnological progress – in relation to contrasting conceptualizations of 'nature' that might broadly be termed either the 'postmodern' or 'ecological'. It argues that despite the genre's apparent preoccupation with technologically advanced, virtual or urban environments, the concept of 'nature' and 'the natural' remains crucial to dystopian cinema's characteristic critique of authoritarian power structures that restrict individual self-expression, and its interrogation of human individuality and selfhood. Moreover, it suggests that even self- consciously postmodern dystopias are rooted in the experience of embodiment, and point towards a reconceptualized idea of 'the natural' that is shaped by, and often fused with, technology.