Sudden cardiac arrest is one of the leading causes of death in patients with heart failure (HF). The implantable cardioverter-defibrillator (ICD) is the only evidence-based treatment strategy for patients who have survived a life-threatening ventricular arrhythmic event. Randomized clinical trials have shown that specific subsets of HF patients with ischemic and nonischemic dilated cardiomyopathy benefit from ICD therapy for primary prevention of sudden cardiac arrest. Cardiac resynchronization therapy has become the device-based therapy of choice for improving symptoms and survival in severe HF patients with evidence of ventricular dyssynchrony. This review summarizes the current status of ICD therapy in treating HF patients based on randomized clinical trials and current practice guidelines.