Background: Sustainable development in health field is crucial due to its impact on global environmental and human health. Nurses, as the largest workforce in healthcare, are essential in achieving sustainable development goals by implementing sustainable practices and advocating for a climate-resilient future. Aim: to evaluate effect of sustainable development educational program in health field on staff nurses' knowledge and practices. Methods: a quasi-experimental design was utilized in this study that was conducted at El Hawamdeya General Hospital, Egypt on a convenient sample of 30 staff nurses. Two tools were utilized as follows: (1) Nurses' sustainable development knowledge test questionnaire consisted of two parts apersonal and work-related characteristics, b- sustainable development knowledge test (23 questions). (2) Nurses' sustainable development practices observational checklist (54 items). Results: There were statistically significant differences in staff nurses’ sustainable development total knowledge mean scores (f=1240.52, p=.000) immediately post-program and three months later than pre-program as well as statistically significant differences with marked increase in all dimensions of staff nurses’ sustainable development total practices mean scores (f=91.59, p=.000) immediately post-program and three months later than pre-program. Also, the current study findings revealed a negative statistical correlation between the staff nurses’ total mean scores of sustainable development knowledge and their total mean scores of sustainable development practices. Conclusion: The educational program had positive effects on staff nurses’ sustainable development knowledge and practices. Recommendations: Develop in-service policies and guidelines as well as training programs for sustainable development and incorporate sustainable development courses at different levels of in nursing curricula.