As the lifespan increases, special attention has been given to the supportive care needs of the elderly. Frailty is an important issue in third age, since it is related to poor quality of life and mortality. The prevalence of pathological conditions related to sodium levels, specifically hyponatremia, is also present in the elderly. Yet, it is unclear, if hyponatremia and frailty are related to each other. This review summarizes the current state of knowledge regarding hyponatremia and frailty and analyzes five independent studies which searched for an association between those two parameters. As indicated by this study results, hyponatremia consists a risk factor for frailty. This could be explained by an effect of hyponatremia on sarcopenia and on cognitive function, which consist components of frailty. Thus, it is essential to monitor sodium levels in the elderly and to develop related interventions (e.g. using arginine vasopressin antagonists) in order to prevent frailty.