Background: The concept of frailty has been suggested to comprise physical, mental, and social phenotypes. However, there is no general consensus about the appropriate components for assessing frailty. Objectives: The purpose of this study was to reach consensus on components of frailty assessment using the Delphi process. Methods: To achieve consensus on the definition of frailty, a modified Delphi method was used. Geriatric and gerontologic experts were selected from various fields. The detailed components of frailty were composed of data from the Korean Frailty and Aging Cohort Study. Establishing consensus and collecting opinions from experts were conducted using a modified Delphi method. Results: Overall, nine domains with 14 components of frailty assessment were accepted. There was consensus on the necessity of a broad phenotype including physical, mental, and social frailty. Conclusions: Consensus on the components of a frailty assessment in a clinical setting is achieved through the Delphi process to establish a new tool of frailty assessment.