Leuco vat dye preparations in granular form, containing as their essential components leuco vat dyes, alkaline metal hydroxide and a mixture of 10 to 100 wt.% of an alpha -hydroxy-C1-C4-alkyl sulphinic aid, one of its salts or derivatives and 0 to 90 wt.% of hydrosulphite as a reducing agent, and the production of these preparations and their use in dyeing cellulose-containing fabrics.
