Background: Extreme weather events brought on by climate change have an impact on human health both directly and indirectly. Increased temperatures and heat domes can exacerbate heart, lung, and renal diseases as well as cause heat stress and heat stroke. Nurses are essential in assisting communities in adapting to climate change and in fighting for a more sustainable future on behalf of patients and the environment. Objective: The current study aimed to explore the effect of climate change on health and critical care nurse's practice. Subjects and methods: Design: Descriptive exploratory design was used.Setting: The study was conducted at the New Elkasr ElAini Teaching Hospital in Cairo, Egypt. Sampling: A convenient sample of 84 nurses working in ICUs and Emergency Unit was used for conduction of this study.Tools:Two tools, 1^st one structured interview questionnaire, 2^nd tool, observational guide about the effect of climate change on health and nursing practice. Results: The majority of the studied nurses think that climate change causes harm for people and patients. Three quarters of the studied nurses think that climate change causes malnutrition or hunger due to rising food prices. About two-third of the studied nurses thinks that climate change causes violence, physical and mental harm respectively. Conclusion: Nurses' awareness of climate change and how it relates to health and practice varied. The role of nursing in combating climate change remained unclear. The study made clear that critical nurses did not immediately understand their responsibility in combating climate change. Include climate change in nursing courses so that future nurses will have the right attitudes toward environmental sustainability.