The present invention relates to an apparatus for cooling material to be printed and printing machine elements at sheet-fed rotary printing machines by means of cooled compressed air. It is an object of the present invention to provide an apparatus which requires little space, is able to cool effectively the material to be printed as well as the machine elements, which are undesirably heated by the dryers. Pursuant to the present invention, this objective is accomplished by providing an apparatus wherein cooled, compressed air is supplied over one or more sheet-guiding devices for guiding the sheets pneumatically along the sheet-guiding path, and a cooling device is disposed in the cross section of flow of the compressed air or the sheet-guiding device.