Aims and objectives: This article presents findings from a dietary intervention designed to improve the nutritional knowledge, attitudes, intentions and dietary intake of socially disadvantaged children. Design: Quasi-experimental design. Methods: A total of 201 (treatment group n = 106, control n = 95) children completed the questionnaire at pre- and post-test. Data from 99 participants from the treatment group were included at 12-month follow-up. The treatment group received a dual intervention of computer-based and traditional methods for 3 consecutive weeks. Results: The findings show no significant differences in scores of dietary knowledge and intentions between pre- and post-measures in both treatment and control groups. At post-test, however, the treatment group reported a better knowledge score, a significantly higher intention to limit unhealthy food and a more negative attitude towards less healthy food than the control group. The results of the short-term evaluation suggest that only the treatment group showed a significant reduction in unhealthy food consumption and a significant increase in vegetable intake. Nevertheless, at follow-up, these effects were not sustained. Prospectively, however, we found a predictive effect of dietary knowledge and intentions on food intake at follow-up. Conclusion: Given the relatively short-term effects achieved by the intervention, it remains crucial to understand the aspects of short-term interventions that may lead to longer term effects, as well as the mechanisms underlying dietary intake among this group of children.