Nutrition education on healthy eating during childhood plays an important role in ensuring healthy growth process of children. One method of doing so is by using age-appropriate education tools. This cross-sectional, quasi-experimental study was to assess the effectiveness of interactive book, which had its content appropriateness assessed, as an education tools in improving knowledge level on healthy diet among preschoolers. 116 subjects aged 4-6 years (60±10 months) were recruited and randomly grouped into intervention group and control group (each with 58 subjects) from five kindergartens in Bangi, Selangor where only those subjects from intervention group were exposed to the interactive book prepared prior to this study. A same set of questionnaires, with a total score of 32, was used to assess changes in subjects’ knowledge levels at Pre-test (before intervention), Post-test I and Post-test II (one-week after Pre-test), where Post-test I only involved subjects from intervention group. At Pre-test, the intervention group scored 25±5, while the control group scored 26±4. After intervention, mean score for intervention group increased to 29±4 for both Post-test I and Post-test II; whereas it remained relatively unchanged for control group for Post-test II (26±5). Significant increase in knowledge level (p<0.001) was found in intervention group, both after intervention and effect of group*time, compared to control group (p=0.077). Hence, this study proved that interactive book could potentially be an effective education tool in nutrition education and improving knowledge level on healthy diet among preschoolers and children.