The present invention relates to a composition for dyeing keratin fibres, in particular keratin fibres such as the hair, comprising: a) at least one oxidation base 3-(2,5-diaminophenyl)-1-propanol and/or acid salts thereof and/or solvates thereof such as hydrates b) at least one coupler c) at least one polymer chosen from cationic polymers and amphoteric polymers, and mixtures thereof d) at least one fatty substance the total amount of fatty substances being at least 10%, e) optionally at least one basifying agent and f) optionally at least one chemical oxidizing agent. The invention also relates to a process for dyeing keratin fibres such as the hair using the composition of the invention, and to a multi-compartment device for using the composition of the invention.
