PURPOSE: To provide a new fiber-reactive disazo compound useful for dyeing of cotton, etc., by which the dyeings obtained are oxford blue and have excellent co-solubility, dyeing properties, light fastness and wet fastness.

CONSTITUTION: This compound expressed by formula I [D is formula II (R3 is H, -COOH, -SO3H; R4 is H, a 1-4C alkyl or 2-4C hydroxy alkyl; Q is heterocyclic fiber reactive radicals or the like) or the like; R1 is the same as R3; R2 is the same as R4; Z is formula III]. For example, a compound of formula IV is prepared by reacting 1-amino-8-hydroxynaphthalene-3,6- or -4,6-disufonic acid with a diazonium salt of amine of formula II at one side or a diazonium salt of amine of formula VI at the other side, for example.