Heart failure (HF) and frailty are two distinct yet commonly associated conditions. The interplay between the two conditions is complex, due to overlaps in underlying mechanisms, symptoms and prognosis. The assessment of frailty in patients with HF is crucial, as it is associated with both unfavourable outcomes and reduced access and tolerance to treatments. However, to date a consensus definition of frailty in patients with HF remains lacking and the need for a validated assessment score, for identifying those HF patients with frailty, is high and timely. This position paper proposes a new definition of frailty for use by healthcare professionals in the setting of HF and creates a foundation for the design of a tailored and validated score for this common condition.