Blends of cis-polyisoprene (CPI) and nitrile butadiene rubber (NBR) in different volume ratio were prepared to see the effect of composition on different properties. Structure characterization has been done through X-ray diffraction and scanning electron microscope. Scanning electron micrographs confirm homogeneous nature of all the blends. The dynamic mechanical analyzer was used to measure damping, storage modulus, glass transition temperature and mechanical properties (Young's modulus and tensile strength) of these blends. Activation energy and fragility were determined for the non-Arrhenius (fragile) behavior of viscosity using Vogel-Fulchuer-Tammann (VFT) equation. Thermal conductivity has been analyzed through thermal constant analyzer. Results indicate that all the measured properties are dependent on blend composition and crosslink density.