Voltage-gated potassium channels encoded by KCNQ 1-5 (termed Kv7.1 – 7.5) have been identified as crucial regulators of neuronal membrane potential and cardiac action potential. However, Kv7 channels are not the preserve of these two cell types as extensive recent studies have revealed Kv7 channels especially Kv7.4 and Kv7.5 promote vascular smooth muscle dilatation and relax non-vascular smooth muscles such as uterus, colon or bladder. These activities are consistent with activation of low threshold potassium channels leading to stabilization of a negative membrane potential. This lecture will provide an overview of this emergent area of research. In addition it will highlight more recent discoveries that Kv7 channel function is impaired considerably in cardiovascular disease and that activation of Kv7.4 underlies vasorelaxant responses to agonists of β-adrenoceptors and other cAMP linked receptors (eg CGRP). The combination of these two findings provides an explanation for the generalized reduction in vasodilatory effects in hypertension. These findings consolidate the view that Kv7 channels may be master regulators of vascular smooth muscle contractility. They are also likely to be as important in receptor-mediated regulation of visceral smooth muscle although the existence of multiple cell types in visceral tissues makes the situation more complicated.