Major advances have been made over the last decade towards the elucidation of the molecular mechanisms involved in the endothelium-dependent regulation of vascular tone and blood flow. While the primary endothelium-derived vasodilator autacoid is nitric oxide, it is clear that epoxyeicosatrienoic acids and other endothelium-derived hyperpolarising factors, as well as endothelin-1 and reactive oxygen species, play a significant role in the regulation of vascular tone and gene expression. This review is intended as an overview of the signalling mechanisms that link haemodynamic stimuli (such as shear stress and cyclic stretch) and endothelial cell perturbation to the activation of enzymes generating vasoactive autacoids.