The dynamic Young's modulus and damping capacity of each of 14 samples of same viscose spun rayon yarns and fabrics treated with several contents of urea-formaldehyde resin were measured by the vibrating reed method in vacuum at room temprature, and obtained the following results:1) In the observation of the influence of the resin content on the dynamic Young's modulus of yarn and fabric treated with resin, it was found that the dynamic Young's modulus was increased as the resin content was increased and that the values of dynamic Young's modulus of every treated yarn was higher than the values of corresponding fabrics. (see Fig. 4)2) By measuring the influence of the resin content on the damping capacity of yarn and fabric treated with urea-formaldehyde resin, it was found that the variation of the values of damping capacity with various resin contents on yarn or fabric was not distinct, although the values of the damping capacity of every treated fabric were higher than thoes of corresponding yarns. (see Fig. 5)