Background: Dengue is spread through the bite of an infected mosquito. A pregnant woman already infected with dengue can pass the virus to her fetus during pregnancy or around the time of birth. Dengue can have harmful effects, including death of the fetus, low birth weight, and premature birth. Aim: To determine the efficacy of implementing educational program on pregnant women's knowledge and practices regarding preventive measures of dengue fever. Subjects and method: Design: A quasi-experimental research design was used to fulfill the aim of this study. Setting: The study was conducted in the Antenatal Outpatient Clinics at Mansoura University Hospital. Subjects: Based on the non-probability purposive sampling technique, a sample of 100 pregnant women was selected. Three tools were used: Tool (I) structured interview questionnaire, Tool (II) pregnant women's knowledge regarding preventive measures of dengue fever, and Tool (III) pregnant women's reported practice regarding preventive measures of dengue fever, (pre/post). Results: A statistically significant difference was detected between pregnant women's level of knowledge and practice regarding preventive measures of dengue fever after implementing the educational program. Also, the study demonstrated that there was a highly statistically significant correlation between pregnant women's knowledge and practice regarding preventive measures of dengue fever at (P= <0.001) after implementing the educational program. Conclusion: implementing educational program has a positive effect on improving pregnant women's knowledge and practice regarding preventive measures of dengue fever. Recommendations: Implementing an educational program on pregnant women's knowledge and practices regarding preventive measures of dengue fever is recommended in various maternity healthcare settings. Educational booklets should be provided about dengue fever for pregnant women, in addition to replication of the current study with a larger sample of patients undergoing cardiac surgery in different settings is required for generalizing the results.