Wire myography is a common ex vivo technique used to study vascular reactivity and the functional responses of small blood vessels (internal diameter 60-1000μm) in pregnancy and in numerous pathologies such as hypertension, diabetes, atherosclerosis and aging. In these diseases, the inside lining of blood vessels is damaged so that the vessels cannot dilate and function properly. A fundamental therapeutic approach in cardiovascular disease is to improve the ability of blood vessels to dilate and therefore, improve blood flow to key organs. In wire myography, blood vessels from a variety of species are isolated from surrounding tissue, cleaned of fat and cut into ring segments. Two stainless steel or tungsten wires are then threaded through the lumen of a vessel segment and attached to two jaws. The vessel is maintained in an individual organ bath containing physiological saline solution at 37°C and bubbled with carbogen (95% O2 & 5% CO2). The vessels are normalised to an equivalent of ~60mmHg to mimic the in vivo environment of the vessel for isometric measurement. Using this technique, we can assess the ability of the blood vessel to dilate or constrict. Furthermore, it is possible to study the vascular signaling mechanisms using pharmacological agonists and antagonists, or transgenic animals. Over the past decade, wire myography has been instrumental in our current understanding on how blood vessels dilate in physiological and pathophysiological conditions. More importantly, it has contributed to the development of novel pharmacological treatments for vascular diseases.