Abstract : Frailty in the elderly is an important factor of morbidity, particularly in the setting of surgery. The various pathologies that can lead to a functional decline are well known. The risk of mortality and morbidity should be assessed as a function of the nature of the surgical procedure and of the disease for which it is required; the factors of severity, the predictable duration of the procedure, and the expected blood losses must also be taken into account. The thrombo-embolic risk should finally be considered. In the elderly, one may say that the functional risk matters more than the vital risk. Frailty must be integrated into the risk assessment; however, further studies are needed to better determine the impact of that new concept. Undoubtedly, the cognitive and nutritional status are of main importance. A better knowledge of the risks should lead to validate specific interventions that could help to prevent surgical complications, shorten the length of hospital stay, and protect the self-sufficiency of the aged.