To understand and analyze the concept of “unbearable suffering” using a concept analysis method and to propose a new nursing diagnosis, the Walker and Avant method of concept analysis was used. Following the concept analysis method in 8 steps, a literature search was carried out in the MEDLINE, Dialnet, WOS, and PsycINFO databases between 2016 and 2020. Articles of theoretical or empirical nature, written in English, with the abstract available were included. As a result, 11 articles (4 theoretical and 7 empirical) were included. In addition, 2 cases were developed. The proposed new diagnosis, “unbearable suffering,” refers to the situation of an individual who, because of a variety of factors, regardless of the cause, feels that he/she is unable to bear the suffering he/she is experiencing. The diagnosis is proposed for inclusion in “Domain 9: Coping/Stress Tolerance” and “Class 2: Coping Responses” of the North American Nursing Diagnosis Association taxonomy. Recognition of a nursing diagnosis for unbearable suffering could be key in identifying this type of suffering and facilitating interventions to reduce or mitigate it. Nurses play a fundamental role in situations of high levels of end-of-life suffering.