Eco-friendly method for paper dyeing with reactive dyes. The authors pre-evaluated possible application of kayacelon dyes (synthesized in the Institute of Polymer and Dye Technology, Technical University of Lodz) in paper dyeing combined with a polyelectrolyte - polycondensate of hexamethylene -1.6 diamine and guanidine. In the light of the research results presented here, the dye and retention agent dyeing method, which is to be patented, turned out to be very effective. The dye was practically entirely saturated on the pulp fibrous components, fines had good retention parameters contributing in this way to high purity of white water. It is particularly important in the environment friendly production of dyed papers in tightly closed water loops.