Background: Novel interventions within child care settings are needed for childhood obesity prevention. The aim of this study was to determine the impact of a short-term nutrition education pilot intervention on preschool-age children's snack food choices. Methods: Children ages 3-5 years (n = 49) from one child care setting participated in a short-term nutrition education intervention (nine 30-minute interactive lessons) taught over a 2-week period. Pre-post assessments included snack knowledge and snack preference questionnaires and an observed snack selection trial to allow children to choose between a healthy and unhealthy snack choice similar to the current food environment. Children's height and weight were measured and BMI z-scores calculated. Parental reports of demographics and child's food preferences were also collected at baseline. Results: Children significantly improved their preference of healthier snacks (p = 0.03) and the ability to distinguish them (p = 0.03) from other snacks. However, they did not significantly improve (p > 0.05) their snack choice between a healthy and unhealthy choice immediately after the short-term nutrition education program. Children who were younger (p = 0.003) or who had higher nutrition knowledge scores (p = 0.002) were more likely to select the healthy snack after the intervention. Conclusions: This study provides evidence that a short-term nutrition education program improves preschool children's knowledge about healthy snacks, but does not translate to immediate healthier snack selections for all children. Future research should investigate the optimal duration of a nutrition education program in a child care setting and other external influences (parents, policy) most influential on snack choice and eventual obesity risk. (author abstract)