Background: the current drive towards sustainability is putting pressure on organizations and their managers worldwide to apply all measures that can be managed, monitored, and analyzed in a unified custom using some common resources and information under different types of administrative standards. This study aimed to assess the effect of green management educational program on nurses' sustainability management knowledge, nurses' demographics correlate. Methods: a quasi-experimental research design was used. Sample: A purposive sample of 50 different categories of the nursing managers' positions was included in the study. Setting: this study was conducted in Obstetric and Gynecological Hospital at Ksr Elaini hospitals. Tool: An adapted Green Management Knowledge Questionnaire (GMKQ) was utilized to gather the data. Results: The key findings of this study were: there was a highly statistically significance difference in the group subject scores before and after program implementation, and there was no significance difference in their experience, qualifications with their knowledge level. Finally, there were not any demographic predictions/ influencing the knowledge level improvement. Conclusion: Entirely nursing managers' necessity to be mindful of the green management concept, his/ her role as a manager, and how to apply this role. This research recommended a supplementary study on a large scale, including all Egyptian university and governmental hospitals, will be necessary to weigh the level of knowledge at all operational, supervisory, and strategic levels. An enlightening training program must be applied to enhance nursing managers' knowledge concerning green management as a key part of sustainability in general and testing its impact on organizations and patient outcomes.