Background: Dengue (break-bone fever) is a viral infection that spreads from mosquitoes to children. It is more common in tropical and subtropical climates. Assessing mothers' knowledge, attitude, and practices (KAP) is deemed necessary, yet, at present, to the best of knowledge, attitude, and practices. Aim: To determine the effect of educational guidelines on mothers' knowledge, attitude, and practice regarding dengue fever complications prevention among their children. Subjects and method: Design: A quasi-experimental research design was used to fulfill the aim of this study. Setting: The study was carried out in Pediatric outpatient clinics at Sohag University Hospital. Subjects: A purposive sample of 100 mothers involved in the current study from the previously selected settings. Four tools were used: Tool (I) a structured interview questionnaire, was composed of two parts: Part (1): Mothers' personal data, Part (2): Children's personal data; Tool (II) Mothers' knowledge regarding dengue fever, Tool (III) Mothers' attitude regarding dengue fever, (pre/post), and Tool (IV) Mothers' practice regarding dengue fever. Results: A statistically significant difference was detected between pregnant mothers' level of knowledge, attitude, and practice regarding dengue fever complications prevention among their children after educational guidelines implementation at (P= <0.001). Conclusion: Educational guidelines implementation has positively affected mothers' knowledge, attitude, and practice regarding dengue fever complications prevention among their children. Recommendations: Educational instruction implementation regarding dengue fever is recommended in various maternity healthcare settings. Educational booklets should be provided about dengue fever complication prevention for mothers and taught using the booklet and illustrated pamphlets for each one to improve their knowledge.