Frailty is a concept that is better than multimorbidity at identifying older people in need of special multidimensional care. Frailty denotes a state of accelerated biological aging in which the body gradually loses the ability to handle physical, mental and social stress. It is a dynamic condition which can be partly prevented and treated with physical exercise, nutrition and appropriate medication. They are many validated and simple screening tools for frailty. Some of these screening tools can assess the degree of frailty and thereby provide a risk stratification in for example a medical emergency. This can be used to support decisions to offer relevant medical intervention to chronologically old but biologically young people as well as to refrain from treatment in chronologically young but biologically older people.