Background: Covid-19 pandemic with its sudden and widespread global outbreak has stunned health care systems. Nurses are at the forefront of fight against this pandemic, and Intensive care unit (ICU) nurses are more at risk of infection as they have a greater interaction with infected patients. Therefore, the present study was conducted to explore the lived experiences of Iranian ICU nurses in the care of patients with covid-19.Methods: This is an interpretive phenomenological study in which, 15 ICU nurses were purposefully selected. Semi-structured in-depth interviews were used to collect data. The transcripts of the interviews were recorded and then analyzed by Diekelmann (1989) method with hermeneutic approach.Results: Ten of the samples were female and five were male. The mean age of participants was 32 years and their average work experience in the intensive care unit was 6 years. Three main themes were obtained from data analysis, including beyond usual care, the emergence of a new image of nursing and the Realization of professional challenges. Conclusion: Working in difficult and unknown conditions with many challenges caused mental and physical depreciation of nurses in the intensive care unit. However, the nurses showed a spirit of self-sacrifice and did not give up their relentless efforts to fight this unknown enemy, and fulfilled their professional responsibilities to provide the best care to patients. By doing so, the nurses showed a new image of nursing to the society. Therefore, full support should be provided to healthcare workers, especially nurses by the authorities in order to prepare them to respond to unwanted crises.