Bleaching of pulps of mechanical origin in which the pulp is treated with a metal-complexing or sequestering agent and is then washed with an efficiency higher than 95 % before being subjected to the action of hydrogen peroxide at a temperature above 100 DEG C and not exceeding 250 DEG C at the pressure of steam at the said temperature for 1 to 30 minutes, not conjointly with a mechanical beating action.
