The concept and meaning of futile care depends on the existing culture, values, religion, beliefs, medical achievements and emotional status of a country. We aimed to define the concept of futile care in the viewpoints of nurses working in intensive care units (ICUs). In this phenomenological study, the experiences of 25 nurses were explored in 11 teaching hospitals affiliated to Social Security Organization in Ghazvin province in the northwest of Iran. Personal interviews and observations were used for data collection. All interviews were recorded as well as transcribed and codes, subthemes and themes were extracted using Van Manen's analysis method. Initially, 191 codes were extracted. During data analysis and comparison, the codes were reduced to 178. Ultimately, 9 sub-themes and four themes emerged: uselessness, waste of resources, torment, and aspects of futility.Nurses defined futile care as "useless, ineffective care giving with wastage of resources and torment of both patients and nurses having nursing and medical aspects" As nurses play a key role in managing futile care, being aware of their experiences in this regard could be the initial operational step for providing useful care as well as educational programs in ICUs. Moreover, the results of this study could help nursing managers adopt supportive approaches to reduce the amount of futile care which could in turn resolve some of the complications nurses face at these wards such as burnout, ethical conflicts, and leave.