Child accidents are a serious health problem in most countries where accidents are the greatest cause of death of children. Although accidents are considered as a danger but it can be prevented. The aim of the current study was to assess knowledge and practice of mothers regarding accident prevention and first aid for their preschool children, design and implement a health promotion educational program for mothers and evaluate the degree of improvement of mother's knowledge and practice towards accident prevention and first aid. A quasi - experimental research design was used to conduct this study. This study was conducted on MCH centers and at home of mother's who have preschool children in Benha city, the sample was composed of 100 mothers who had a preschool child. Data collection tools were structured interviewing questionnaire for assessing socio-demographic characteristics of mothers and their children and mother's knowledge related to children accidents and prevention of these accidents and mother's practice related to first aid of accidents and Home environment safety measures observation sheet, to observe child home environment safety measures. The results of this study showed that the mean age of mothers was 30.4 ± 6.73, there was general improvement in mother's knowledge and practice regarding accident prevention and first aid after implementation of the health promotion educational program, also home safety measures weren’t exist in most homes of the study sample. There was a highly statistical significant difference between mother's knowledge and practice with their education, occupation and family income. Also there was positive correlation between total mothers’ knowledge and practices after program implementation. The study concluded that there was a general improvement in mother's knowledge and practice regarding accident prevention and first aid after implementation of the health promotion program. the study recommended that provision of health education programs for parents about accident prevention and first aid at MCH centers.