Abstract: A process is provided for the bleaching of cellulose pulp, particularly for the peroxide bleaching of high yield pulp, which comprises forming a suspension of lignocellulosic pulp material; mixing the suspension in a mixing zone with a bleaching agent while adjusting the temperature of the pulp suspension to within the range from about +10.degree. C. to about -10.degree. C. of a temperature within the range from about 40.degree. to about 95.degree. C. at which bleaching is to be carried out; quickly dewatering the pulp suspension to a pulp consistency within the range from about 18 to about 50%, equal to or at most 5% less than the pulp consistency of the pulp suspension charged to the mixing zone; passing the dewatered pulp suspension to the bleaching zone before its temperature can change substantially from the adjusted temperature; carrying out the bleaching with a bleaching agent at the selected bleaching temperature within the range from about 40 to about 95.degree. C.