The purpose of this paper is to provide a contribution towards increasing knowledge on how healthy food stimuli can improve eating behaviour, by making a comparison between advergames' food content effects on children's food choices, product liking and nutritional knowledge. A sample of 231 elementary-school-age children (7 and 8years old) was randomly assigned to one of the following tasks: (i) playing the healthy advergame and (ii) playing the less healthy advergame. A post-treatment pictured questionnaire was used to assess children's behaviour in terms of immediate food choice, food liking and nutritional knowledge, following exposure to treatment. Results show that children tend to choose according to what was being advertised in the game. In terms of food liking, children who played the less healthy version of the game report a higher preference for some of the less healthy options. Regarding children's nutritional knowledge, no differences between groups were registered, indicating that children already have a solid understanding of what are 'good' and 'bad' foods for their health. Our findings are aligned with previous research on dual-process model: although children's nutritional knowledge is good, they might not employ it when selecting snacks. According to these results, legal, educational and management contributions should be employed: regulation should protect children from less healthy contents on advergames; schools may use digital games to promote healthier eating habits; enterprises can invest on this market opportunity (healthy food targeting children); and finally, social marketing can use advergames in order to reduce child obesity.