Ether-à-go-go-related gene (erg) channels are voltage-dependent K+ channels mediating inward-rectifying K+ currents because of their peculiar gating kinetics. These characteristics are essential for repolarization of the cardiac action potential. Inherited and acquired malfunctioning of erg channels may lead to the long QT-syndrome. However, erg currents have also been recorded in many other excitable cells, like smooth muscle fibres of the gastrointestinal tract, neuroblastoma cells or neuroendocrine cells. In these cells erg currents contribute to the maintenance of the resting potential. Changes in the resting potential are related to cell-specific functions like increase in hormone secretion, frequency adaptation or increase in contractility.