Abstract: Process for producing a water-soluble core for pressure die casting by pre-drying a granular water-soluble salt having grain size of less than about 1000 microns so that the moisture content thereof becomes less than 1%, molding under compression the granular water-soluble salt into a desired shape and volume at a pressure of between about 1.5-4 tons/cm..sup.2, and if necessary, sintering the molded salt at a temperature of between about 100.degree.-300.degree.C. The core for pressure die casting acting as a cavity former within a casting and substantially consisting of a water-soluble salt and having a compressive strength of between about 800-1480 kg./cm..sup.2, a bending strength of between about 200-370 kg./cm..sup.2, and a density of between 2.05-2.12.