The article discusses the intersections of gender and humanity in the re-imagined television series Battlestar Galactica (USA/UK 2003–2009) in relation to the “original” series Battlestar Galactica (USA 1978–1979) and its spin-off Galactica 1980 (USA 1989), connecting and contextualizing the series to their cultural backgrounds and the science fiction genre. Perhaps the most noticeable features that differentiate the re-imagination from the earlier versions are its way of representing gender and developing the relations between humans and machines. All the series deal with the confrontations between humans and machines, but in the re-imagined series the robotic machines, cylons, of the earlier series have developed into humanlike creatures that have infiltrated human societies. In order to be accepted as humans, or pass for human, the cylons must perform humanity believably, and gender seems to play an important role in the processes of passing. The article asks how the boundaries of gender and humanity are produced in the series through the representations of human and cylon characters.