Abstract: A packing sheet for a heat exchange packing has an undulating shape composed of a first substantially transversely extending sine wave superimposed with a second substantially longitudinally extending sine wave. A plurality of substantially longitudinally extending recesses and a plurality of substantially transversely extending recesses each having an undulating surface are thereby defined.A plurality of the packing sheets may be disposed in vertical parallel relationship with alternate sheets reversed to form a heat exchange packing in which the facing recesses define substantially vertically extending channels and the facing recesses define substantially transversely extending channels. The channels present a low pressure drop to liquid to be cooled and to a cooling gas and yet provide tortuous paths for the liquid and gas. Thus, the packing is able to provide efficient heat exchange and yet have a low power requirement.