Idiopathic ventricular fibrillation is diagnosed in survivors of sudden cardiac death that has been caused by ventricular fibrillation without known structural or electrical abnormalities, even after extensive investigation. It is a common cause of sudden death in young adults. Although idiopathic ventricular fibrillation is a diagnosis of exclusion, in many cases only a partial investigation algorithm is performed. The aim of this review is to present a comprehensive diagnostic evaluation algorithm with a focus on diagnostic assessment of inherited arrhythmic syndromes and genetic background.