Disclosed are reactive dyes, and the use thereof, according to the formula(R--U).sub.n D--(X).sub.r,in which D is the radical of a monoazo, polyazo or metal complex azo dye; U is --CO-- or --SO.sub.2 --; R is a radical of the formula ##STR1## Z is sulfatoethyl, .beta.-thiosultafoethyl, .beta.-phosphatoethyl, .beta.-acetoxyethyl, .beta.-halogenoethyl or vinyl; alk is straight-chained or branched C.sub.1 -C.sub.6 -alkylene; Y is hydrogen, chlorine, bromine, fluorine, hydroxyl, sulfato, C.sub.1 -C.sub.4 -alkanoyloxy, cyano, carboxyl, alkoxycarbonyl having 1 to 5 C-atoms, carbamoyl or a radical --SO.sub.2 --Z in which Z is as defined above; V is hydrogen or C.sub.1 -C.sub.4 -alkyl unsubstituted or substituted by carboxyl, sulfo, C.sub.1 -C.sub.2 -alkoxy, halogen or hydroxyl or is a radical ##STR2## in which Z, alk and Y are as defined above; R.sub.1 is hydrogen or C.sub.1 -C.sub.6 -alkyl; alk' are independently of each other straight-chained or branched C.sub.2 -C.sub.6 -alkylene; n is 1 or 2, r is 1 or 2, m is 1 to 6, p is 1 to 6, q is 1 to 6; and X is a reactive radical comprising a halogenotriazine, halogenopyrimidine, halogenoacryloyl, halogenopropionyl, .beta.-halogenoethylsulfonyl, .beta.-sulfatoethylsulfonyl or vinylsulfonyl group, with the proviso that if D is a monoazo dye X must comprise a halogenotriazine or halogenopyrimidine group.