Although sudden cardiac death in youths is generally rare, it is estimated that 10% to 20% of these deaths occur in previously healthy infants, children, adolescents and young adults without any findings on autopsy and with devastating consequences on the family. The majority of these deaths are caused by inherited arrhythmia syndromes, the so-called 'channelopathies'. In the present paper, the recent advances in the clinical and genetic background of long QT syndrome, short QT syndrome, catecholaminergic polymorphic ventricular tachycardia, Brugada syndrome and the overlapping phenotypes are reviewed, and the recently established connections between these syndromes and idiopathic ventricular fibrillation and sudden infant death syndrome are discussed.