The viscoelasticity and morphology of an organic hybrid of chlorinated polyethylene (CPE) and N,N'-dicyclohexyl-2-benzothiazolyl sulfenamide (DBS) were studied by means of tensile and shear complex modulus and differential scanning calorimetry (DSC) analysis. Tensile and shear loss modulus (E" and G"), which are shown as indexes of vibration damping performance, showed one peak corresponding to the glass transition. The peak maximum values (E"(max) and G"(max)) increased in proportion to DBS content (phi DBS) and the slope of E" against phi DBS became steep above a certain DBS content, i.e. the critical DBS content (phi c). A high damping material was obtained by the addition max of DBS, especially when DBS content was higher than phi c. These increases in loss moduli below and above phi c are caused by the interaction between CPE and DBS molecules and the friction between DBS molecules, respectively. It was found that CPE/DBS is a compatible blend at all DBS contents from the analysis of the glass transition temperature with DSC. Furthermore, the influence of chlorine content in CPE on those characteristics was investigated. Higher chlorine content led to lower phi c, a decrease in E" below phi c and an increase in E" above phi c. These results are due to the increase in the number of dichloromethylene units (CCl2), which reduces the alpha-hydrogen atom in CPE.