The invention relates to a composition for dyeing human keratin fibers such as the hair, in foam form, comprising at least one alkaline agent, at least one oxidizing agent, at least one oxidation dye precursor and at least one polycondensate of ethylene oxide and of propylene oxide of structure (I) below: H—(O—CH2—CH2)a(O—CH(CH3)—CH2)b—(O—CH2—CH2)a′—OH, in which a, a′ range from 2 to 150, and b ranges from 1 to 100. The invention also relates to a process for dyeing human keratin fibers using this composition. A subject of the invention is also a device for dyeing keratin fibers, comprising the composition of the invention in liquid form and a foam dispenser for delivering the composition in the form of a foam.
