The aim of the experiment was to evaluate the effect of different mulch materials on the occurrence of Colorado Potato Beetle, weed biomass and especially on the yield of ware potatoes. The experiment with different types of mulching (grass mulch, black textile mulch, non-mulched control) and 2 varieties (Finka and Katka) was carried out under organic system in 2009. The results showed that the grass mulch was the best mulching material for reaching the highest yield, where an increase of the yield of ware tubers by 6.6 - 7.8 t/ha in comparison with non-mulched control variant was observed. In the experiment the mulching of organic potatoes had a positive effect on a lower activity of an oviposition of Colorado Potato Beetle and a consecutive occurrence larvae by the variant with the grass mulch, a lower weed infestation by the variant with the black mulch textile in comparison with non-mulched control