The object of this study is to estimate the theoretical value of Shore hardness. The value of Shore hardness is determined generally by the height of rebound of a falling indenter which will depend upon the elastic and restitution properties of the specimen. If the equation showing the relation between the static load and the depth of indentation is applicable to the dynamic indentation, the energy which determines the height of rebound of hammer can be deduced theoretically on the basis of that equation. A comparison of the theoretical Shore hardness numbers and experimental ones of some specimens shows a good agreement between them.