In this article, the authors explore a vital, if rarely focused upon, space in early childhood settings (0-5 years): the bathroom. In bathrooms, more or less fundamental biological, self-care, and "civilising" (Elias 1978) processes are performed by children, such as those related to personal hygiene, the management of bodily discharges, the maintenance of the body and improvement of its appearance, and learning about appropriate social and private conduct of oneself in relation to these. In this article, the authors begin to examine the preschool bathroom as a site for the workings of power in general and biopower in particular, and more specifically as an institutional context in which strategies and techniques that seek to shape children's subjectivities in relation to health are mobilised. Following the introduction, the authors provide a brief overview of some ways in which power was analysed within early childhood settings and describe their data. In the findings, the authors deliver their analysis of power by providing their own empirical examples collected in the bathroom of a case study preschool in Australia. They employ two analytical questions to focus their analyses and the presentation of findings: how are children's bodies and conduct regulated within the preschool bathroom, and to what extent is this bathroom a site for the mobilisation and exercise of biopower? (Contains 2 notes.)