There is increased awareness of the impact of gender and gonadal steroids on human cardiac rhythm and arrhythmias; e.g., drugs that prolong repolarization induce torsades de pointes (TdP) more frequently in women than men; female gender is an independent risk factor for syncope and sudden death in the congenital long QT syndrome; and the higher propensity toward arrhythmia in normal females is associated with fundamental differences in repolarization such that rate-corrected QT intervals are longer in females than males. Mechanisms underlying these differences are incompletely defined but are believed to involve gonadal steroids. This review discusses recent advances and prospects for further elucidation of the influence of gender and gonadal steroids on ventricular repolarization and arrhythmias.