Selected compositional, processing, design, and testing factors are discussed with respect to their influence on the dynamic properties of elastomeric parts. Variations in rubbers, fillers, oils, and level of cross-linking produce specific changes in spring rate and damping coefficient. Processing factors such as mixing, curing, and storage are shown to have an important influence on dynamic properties. Design concepts relating material properties and the dynamic response of some simple shapes are reviewed, along with the effect of prestrain and strain history.