Objective: Early childhood services have been identified as key settings for promoting healthy eating and obesity prevention. However, little is known about the obesity-related behaviours of preschool-aged children or food-related policies in these settings. The purpose of this study was to describe the contents of preschoolers’ lunchboxes to inform future interventions. Methods: Cross-sectional survey of 259 children attending preschools in the Sydney West and Sydney South West regions of New South Wales in 2008. Lunchbox data were collected using a purpose-designed audit tool. Food and beverages were classified as fruit, vegetables, dairy, breads and cereals, ‘extra’ (energy-dense) foods, ‘extra’ drinks or water. Results: Sandwiches and home-cooked meals were the most frequently identified food item, found in 92% of children’s lunchboxes, followed by fresh fruit. However, 60% of lunchboxes contained more than one serve of extra food or drink. Conclusion: While nutrition guidelines allow one to two serves of extra foods per day for preschool-aged children, the majority of children appear to consume most of this allocation during their school day, potentially contributing to overconsumption of extra foods and excess kilojoule intake. Implications: Preschool food policies may help to guide the content of children’s lunchboxes, however this study emphasises the need for better communication and enforcement of these policies, as well as broader public policy changes.