The effect of application of organic fertilizers in defined doses on structure of Carabid communities was studied. The Carabids were pitfall trapped, in 2004 2006 on experimental plots in the university farm in Kolioany District of Nitra, S N Slovakia, in 5 variants 1st unfertilized; 2nd 25 t ha-1 farmyard manure, 3rd 50 t ha 1 bio sludge; 4th 50 t ha 1 farmyard manure; 5th 100 t ha 1 bio sludge to the selected rotatio 2004 Helianthus annuus, 2005 Beta vulgaris, 2006 Zea mays. The area of each variant was 1,800 m2. During the three-year period were obtained 16,172 individuals of Carabids belonging to 32 species. The distribution within the individual variants fluctuated as follows 1st variant 10 13 sp. and 612 1,904 ind. 2nd variant 12 15 sp. and 1,147 1,516 ind., 3rd variant 8 13 sp. and 360 3,127 ind.; 4th variant 7 9 sp. and 371 832 ind.; 5th variant 8 10 sp. and 404 1,072 ind. The dominant species in all variants were Pseudoophonus rufipes and Poecilus cupreus, while Calathus fuscipes, Anchomenus dorsalis, Carabus scheidleri, Brachinus crepitans were subdominant or recedent. However in individual varities and years they also reached dominant position. The high dominance of Pseudoophonus rufipes caused low values of the Shannon Wiever s diversity index ranging from 0.59 to 1.18. Based on maximum numbers of species and individuals, the most suitable were the 2. and 3. variants, 25 t ha 1 farmyard manure and 50 t ha 1 bio sludge. Out of the applied organic fertilizers, the climatic factors also played an important role.