Abstract We investigated the influence of the biomechanical behavior of human common carotid arterial wall on the NMR proton relaxation times using a Bruker Minispec at 4 MHz. The study was limited to low extension in simple longitudinal elongation of the carotid wall (the maximum loading stretch ratio being 40%). Twenty-five carotid samples divided into 2 longitudinal strips were tested. The first strip was used to determine the nondimensional elastic parameter α according to the mechanical model of Fung. The second strip was used to measure the proton relaxation times. T 1 value was 316.8 ms ± 27.6 and T 2 value was 59.9 ms ± 6.8. A significant linear correlation was found between T 1 and Lnα ( p = 0.02). T 1 and T 2 were not correlated to the age but linearly correlated to the tissue water content ( p < 0.0001), however the age and α were not correlated to the tissue water content. These results may reflect the differences in the amount of water binding sites of the elastin which is involved in the elasticity of the carotid wall at low extension.