Objective: To determine the impact of an implementation intervention designed to introduce policies and practices supportive of healthy eating in centre-based child-care services. Intervention strategies included staff training, resources, incentives, follow-up support, and performance monitoring and feedback. Design: A quasi-experimental design was used to assess change over 20 months in healthy eating policy and practice in intervention and comparison child-care services. Setting: The Hunter New England (HNE) region of New South Wales (NSW), Australia. Subjects: All centre-based child-care services (n 287) in the intervention region (HNE) were invited and 240 (91% response rate) participated. Two hundred and ninety-six services in the rest of NSW were randomly selected as a comparison region and 191 participated (76% response rate). A sub-analysis was conducted on those services that provided children food (n 196 at baseline and n 190 at follow-up). Ninety-six provided menus for analysis at baseline (HNE, n 36; NSW, n 50) and 102 provided menus at follow-up (HNE, n 50; NSW, n 52). Results: Services in the intervention region were significantly more likely to provide only plain milk and water for children (P=0.018) and to engage parents in nutrition policy or programmes (P=0.002). They were also more likely (P=0.056) to have nutrition policy on home packed food. In addition, menus of services that provided lunch were significantly more likely to comply with healthy eating guidelines for sweetened drinks (P0.001), fruit (P0.001) and vegetables (P=0.01). Conclusions: An implementation intervention was able to modify policy and practice in a large number of child-care services so that they were more supportive of healthy eating. (author abstract)