Background: Climate change and environmental degradation are the "major threat" to the health care system in this century. Nurses oversee caring for patients who are suffering from diseases caused by climate change and environmentally irresponsible practices that degrade environments and contribute to climate change. Therefore, nurses must recognize this threat and participate in initiatives that encourage mitigation strategies. Aim of the study: To examine staff nurses' perceptions regarding climate change and its relation to environmental sustainability practice. Design: A descriptive correlational research design was used to achieve the aim of the current study. Sample: A convenient sample (n=150) of staff nurses who agreed to participate in the current study. Setting: The current study was conducted at one of the Egyptian Cairo University hospitals. Tools: Two questionnaires were used as follows; I. Nurses ' perception toward climate change and II. Nurse`s perception toward environmental sustainability. Results: Nearly half (47.06%) of staff nurses' perceived climate change in Egypt. While around half (50.40%) of staff nurses perceived all dimensions of environmental sustainability practice. Moreover, there was a highly statistically significant positive correlation at (p-0.0001, r- 0.42) between total nurses' perceptions about climate change and environmental sustainability practice in nursing. Conclusion: There was a highly statistically positive correlation between nurses' perceptions concerning climate change and sustainability practice in nursing.  Recommendation: Nurse Managers should establish strategies to encourage environmental sustainability in the workplace. In addition, create support policies and practice aimed at reducing healthcare waste and related emissions and development of educational strategies to make nurses more aware of the importance of sustainability in nursing practice to mitigate the impact of climate change.