The field experiments was carried out in the years 1994–1997 at the Agricultural Experimental Stations in Zawady, on cereal-fodder strong soils, in random blocks design in three replications. The target of the analyses was to evaluate the influence of organic fertilization (farmyard manure, rye straw, green manure from post-harvest residues of underplant catch crop of the mixture between black medic and Italian ryegrass with, and without straw additives) on the crop and the sugar beet technological value. During the experiment, the effect of farmyard manure was also compared with the influence of straw and post-harvest residues of underplant catch crop with and without straw additives in terms of size and quality of the sugar beet crop. The use of organic sugar beet fertilizers led to a significant growth of crop of roots, leaves and technological sugar as well as the sugar content itself. One the other hand, it led to a decrease of deformed roots in the roots mass, comparing with the object pattern without the organic fertilization. Among the analysed organic fertilisers, only the post-harvest residues of underplant catch crop did not increase significantly the soluble ash content in the roots juice of sugar beet. The greatest crops of sugar beet and a technological sugar were obtained in the fertilized combination of farmyard manure and post-harvest residues of underplant catch crop with straw. The action of the post-harvest residues of underplant cath crop with straw on the crop growth of sugar beet leaves was significantly higher than with farmyard manure. Straw and post-harvest residues of underplant catch crop with and without straw additives do not differ significantly in the technological value of sugar beet roots, in comparison with farmyard manure.