Sudden cardiac death due to ventricular tachyarrhythmias remains an unresolved problem, probably because the mechanisms responsible for the progression of cardiac disease to electrophysiological failure are poorly understood. Genetically engineered mice, the principal mammalian model for studying cardiac electrophysiology, have contributed to the understanding of the genetic, molecular and systemic mechanisms involved in the initiation and/or maintenance of cardiac arrhythmias leading to cardiac death, e.g. cardiac excitability, conduction velocity and refractoriness. Several murine models harbouring human gene mutations leading to electrical and structural cardiac disorders have been developed, including channelopathies (long QT syndrome), familial conduction disorders, cardiomyopathies and other inherited cardiac disorders. This article reviews the results of the main genetically modified mice addressing the genesis of cardiac arrhythmias and sudden cardiac death.