Short QT Syndrome is a recently recognized inherited channelopathy responsible for sudden cardiac death (SCD) in individuals with a structurally normal heart. It is characterized by abnormally short QTc interval (<360 msec) on the electrocardiogram seen in conjunction with a family history of atrial and/or ventricular fibrillation. It is a genetically heterogeneous disease with mutations in five different genes encoding cardiac ion channels linked to familial or sporadic cases. Based on the chronology of discovery, gain-of-function mutations in KCNH2, KCNQ1, and KCNJ2 have been labeled SQT1, SQT2 and SQT3, respectively. In addition, loss-of-function mutations in two calcium channel genes CACNA1C and CACNB2B have been linked to a new clinical entity characterized by a SQTS and Brugada syndrome phenotype. These have been designated as SQT4 and SQT5, respectively. SCD is a common presenting symptom and has been reported as early as the first year of life, suggesting that SQTS may be responsible for some cases of sudden infant death. Amplified transmural dispersion of repolarization along with abbreviation of the refractory period is thought to underlie the cellular basis for arrhythmogenesis in SQTS. Implantation of an implantable cardioverter defibrillator is recommended for both primary and secondary prevention of SCD. Data regarding a pharmacologic approach to therapy are limited, but quinidine has been identified as being of benefit. This chapter provides an overview of the available literature.