A method of dyeing keratinous substrates, comprising applying onto the keratinous substrates a ready-to-use aqueous composition containing, in a cosmetically acceptable medium:
- a) at least one polyamine compound having at least three amino groups;
- b) at least one nonionic surfactant;
- c) at least one phosphate ester chosen from alkoxylated alkyl phosphate esters and alkyl phosphate esters;
- and
- d) at least one dye chosen from oxidation dye precursors and direct dyes;
- e) optionally, at least one thickening agent;
- f) optionally, at least one alkaline agent;
- g) optionally, at least one fatty substance other than a fatty acid;
- h) optionally, at least one salt;
- and
- i) at least one oxidizing agent.