Kv11.1-11.3 are potassium channels encoded by Ether-a-go-go related genes (ERG1-3 also known as KCNH2, KCNH6 and KCNH7). Kv11.1 encoded by KCNH2 are key components of the cardiac action potential whereas KCNH6 /7 expression is mainly in neurones. These channels exhibit many fascinating structural and biophysical features including a prominent C-type inactivation that make Kv11 channels amenable to blockade by many structurally different agents.  Kv11.1 blockade is responsible for the majority of acquired cardiac arrhythmias and so called 'ERG screens' feature prominently in most drug development programmes. However, ERG expression is not restricted to the heart and brain and in many visceral smooth muscles ERG channels especially Kv11.1 have a key functional role in suppressing contractility. This talk will provide an overview of ERG channels in smooth muscles highlighting the isoform expression in different tissues including portal vein, stomach, jejunum, uterus and bladder. The functional impact of these channels derived from work with pharmacological blockade will also be highlighted.  Work will also be presented on ERG channel expression and function in mouse and human myometrial smooth muscle where functional impact of these channels is lost in pregnancy. The molecular mechanisms behind this functional switch will be highlighted. Overall, this presentation will provide an insight into the role of potassium channels usually associated with the heart in smooth muscle excitability.