In the context of concerns about childhood obesity, mothers are placed at the forefront of responsibility for shaping the eating behaviour and consequently the health of their young children. This is evident in a multitude of diverse sites such as government reports, health promotion materials, reality TV shows and the advice of childcare nurses and preschools. These sites produce a range of resources available to mothers to draw on to constitute themselves as mothers in terms of caring for their children's health. Drawing on a qualitative study of mothers recruited through three Australian preschool centres, this article examines how the working-class and middle-class mothers of preschool-aged children engage with knowledge about motherhood, children and health and how those engagements impact on their mothering, their foodwork and their children. We argue that, unlike the working-class mothers pathologised in some literature on obesity, these working-class mothers demonstrated a no-nonsense (but still responsibilised) approach to feeding their children. The middle-class mothers, on the other hand, were more likely to engage in practices of self-surveillance and to demonstrate considerable anxieties about the appropriateness of their practices for their children's current and future health.