Arteries have been measured for more than 100 years, however a reliable method for mensuration of arterial wall thickness is not available. The reason, among others, for this is that autopsy arterial speciments are not the same as "in vivo", due to agonal and postmorten changes. In this, study different methods to measure the aortic wall thickness are reviewed. A new technique for measuring, instantaneously, the thickness of the aortic wall in chronically instrumented conscious dogs is presented. The method presented here take into account the Furuyama's technique and an algorithm developed in ou~ laboratory.