Device therapy for heart failure has a spectacular development during the last 10 years. Patients with chronic heart failure might benefit from electrical therapy with a view to: (i) resynchronize the failing and dyssynchronized heart and improve its mechanical performance or (ii) prevent the risk of sudden death by automatic defibrillation. These two therapies can be applied together with a combined device, the biventricular implantable cardioverter-defibrillator (CRT-D). Today, the proportion of CRT-D devices among all CRT devices implanted around the world is more than 75% and more than 85% in the USA. This review article will try to answer some important questions for clinical practice: is the growing use of CRT-D devices supported by clinical evidence? Is the risk-benefit profile of CRT-D favourable in particular in mildly symptomatic patients?