The velocities of propagation of longitudinal and transverse ultrasonic waves in epoxidized natural rubber-ethylene propylene diene monomer (ENR-EPDM) blends with EPDM content of 0,25,50,75 and 100 weight percent were measured at a frequency of 2 MHz using pulse echo method. Density of the rubber blend was also measured. Longitudinal modulus, shear modulus, Young's modulus, bulk modulus, Poisson's ratio, crosslink density, and microhardness, of the rubber blends were then calculated. The variations of these parameters with the content of EPDM have been discussed, based on the structural changes of the network.