Frailty is generally defined as a syndrome that combines the effects of natural ageing with the consequences of multiple long-term conditions and is characterised by a decline in body functions and systems. Identification and assessment of frailty is therefore essential to provide adapted geriatric interventions but remains difficult. How to screen and detect frailty? How to assess the level of frailty? Are there clear biological and clinical markers? What are the current tools or medical devices to detect and support frail older adults? What are the latest research findings in this area? What are the keys to tailoring geriatric interventions and avoiding multimorbidity?