The present invention concerns a method for processing molding sand.In order to provide a method with a simple regulating system to control the compressibility of a reclaimed molding sand, the invention proposes that the molding sand be divided into several charges and the processing parameters, such as the quantity of water, the quantity of new sand and/or the quantity of clay to be added, is corrected on the basis of the difference following processing between the actual compressibility and the reference compressibility of the molding sand, measured for the preceding charge.