Abstract: A process for dewatering sewage sludges, the dewatering characteristics of which have been improved by adding an organic flocculant, on a chamber filter press, wherein the greater part of the water in the flocculated sludges is removed by gravity filtration in a process step upstream of the chamber filter press, without application of a pressure difference, and the actual pressure filtration, on the chamber filter press, is only then carried out.In principle, commercial products can be used as the organic flocculant. These are water-soluble, macromolecular compounds which have been obtained by polymerization or copolymerization of acrylamide, acrylic cid and/or their salts, or of esters of acrylic acid or methacrylic acid with specifically modified alcohol components.