Process for the continuous dyeing and printing of piece goods made of synthetic polyamide fibers, preferably blended with cellulosic fibers, using reactive dyestuffs according to a thermofixing method, by applying onto the textile material an aqueous padding liquor or a printing paste, which has been weakly acidified by means of a buffer system of acetic acid and an alkali metal acetate and which contains a fiber-reactive dyestuff whose reactive groups have reversibly been masked by reaction with an alkali metal salt of an N-alkyl-aminoalkyl-sulfonic acid, and after drying of the material fixing the dyestuff on the two fiber components by means of dry heat.