Frailty is a geriatric syndrome due to impaired physiological reserve and characterized by a reduced ability to cope with stressing situations. Frailty and cardiovascular diseases share a common biological pathway and cardiovascular conditions may facilitate the manifestation of clinical frailty. Frailty is identified in 25% to 50% of patients with cardiovascular diseases, with estimates varying depending on assessment methods and population under study. Frail patients with cardiovascular diseases, especially those undergoing invasive procedures, particularly because of coronary artery disease or heart failure, have a substantially higher likelihood of complications and adverse events when compared to robust patients. Gait speed is a simple and reliable measure for objectively identifying frailty in elderly patients with cardiovascular diseases. A performance marker like the 6-minute walking test should be considered for routine use as a prognostic indicator.