The implantable cardioverter-defibrillator (ICD) has established itself as life-saving therapy in patients at risk for sudden cardiac death. Remarkable technological advances have made ICDs easier and safer to implant, with improved therapeutic and diagnostic functions and reduced morbidity. Guidelines on ICD indications have been proposed by American and European scientific societies since a number of years, based upon trials and expert opinion. In the context of variable economic and political constraints, it is questionable whether these guidelines may be applied to all settings. This review discusses the guideline-based indications, critically examines their applicability to clinical practice, and discusses alternatives to ICD therapy.