Abstract: An electrically heated mold for making test specimens of concrete. The mold has two substantially identical mold halves pivotally mounted to each other and electric heating units selectively operated in response to the temperature variations in the concrete of the main structure. Each mold half has a heat transferring wall member which has a mold surface and an outer surface against which one of the heating units is placed. The mold is insulated and has a number of additional features designed to facilitate manufacture and operation of the mold as well as to increase its working life.