Background: Hyperemesis gravidarum refers to prolonged and excessive nausea and vomiting resulting in undesirable maternal and fetal health outcomes, which require hospital admission and extensive medical and nursing care. So, there is an urgent need to increase nurses' performance regarding hyperemesis gravidarum. Aim: The present study aimed to determine the effect of educational program regarding hyperemesis gravidarum on nurses′ performance and women′s outcomes. Subjects and method: Setting:This study was conducted at antenatal units of obstetric departments of Tanta University hospital affiliated to Ministry of High Education, El-Menshawy hospital affiliated to Ministry of Health and Population and EL-Mabara hospital affiliated to Health Insurance. Subjects: The study included all nurses (48 nurses) who are working in the previously mentioned settings, and 144 pregnant women diagnosed with hyperemesis gravidarum during the first trimester of their pregnancy. The studied pregnant women were divided randomly into 3 groups (48 women in each group) pre, immediately post and three months post implementation of the educational program. Three tools were used to collect the data of this study: Tool I: Structured interview schedule for nurses and women, Tool II: An observational checklist for nurses′ practice, and Tool III: Women′s outcomes assessment sheet. Results: The studied nurses' knowledge and practice regarding hyperemesis gravidarum as well as women′s outcomes were improved immediately and three months post implementation of the educational program. Conclusion:The findings of the present study revealed significant improvement in the nurses' performance immediately and three months post implementation of the educational program regarding hyperemesis gravidarum. Recommendations: the study recommended developing continuous educational programs for nurses to enhance and update their performance regarding hyperemesis gravidarum.