The invention relates to cationic aminodianthraquinones containing at least one cationic group Z, Z being chosen from quaternized aliphatic chains, aliphatic chains containing at least one quaternized saturated ring and aliphatic chains containing at least one quaternized unsaturated ring, their use as direct dye in compositions for dyeing keratinous materials, in particular human keratinous fibers such as hair, the dyeing compositions containing them, as well as the dyeing methods using them.