Abstract: Stable, alkaline, granulated dishwashing agent composition containing active chlorine for use in mechanical dishwashers, having a content of builder salts, alkali metal silicates, alkali metal carbonates and, optionally, nonionic surface-active compounds and containing from 1% to 30% by weight of finely divided trichloroisocyanuric acid in the form of granulates or prills with a total surface area as small as possible and having a degree of purity of .gtoreq. 99% as determined by laser-Raman spectroscopy, and from 10% to 40% by weight of granulated alkali metal hydroxide with a total surface area as small as possible.