Objective: to identify the defining characteristics and factors related to the Nursing diagnosis is Frail Elderly Syndrome. Methods: integrative review developed in seven databases, besides the use of Grey literature in Google Scholar and Open Grey. The Problem, Concept, and Context strategies were used to develop the guiding question and select the descriptors. Eight articles and one thesis were included in the final sampling. Results: three new characteristics were identified: Urinary Incontinence; Dysfunctional Family Processes and Sleep Pattern Disorder. The most frequent defining characteristics of the Frail Elderly Syndrome Nursing Diagnosis were: impaired physical mobility; decreased activity tolerance; unbalanced nutrition: less than the body needs and impaired ambulation. Among the related factors, the most present was: impaired muscle strength; cognitive dysfunction, and impaired postural balance. Conclusion: it was found that the three defining characteristics that are not present in NANDA-I need to be further investigated to be included in the Nursing Diagnosis Frail Elderly Syndrome. Contributions to practice: the study provides nurses with a deeper understanding of this diagnosis, supporting and strengthening the clinical reasoning necessary for decision-making to correctly assign the diagnosis to the patient.