The study aimed to assess the effectiveness of meat industry wastewater treatment applying two hybrid systems of activated sludge and ultrafiltration in: (1) an aerobic bioreactor in combination with ultrafiltration and (2) a bioreactor equipped with separate denitrification and nitrification tanks in combination with ultrafiltration. It was found that it is feasible to treat this wastewater in both systems; however, the aerobic bioreactor necessitated the use of a very low activated sludge loading of 0.017 gCOD/g(TS)xd. Consequently, the bioreactor equipped with separate denitrification and nitrification tanks proved to be more favourable. The substrate loading of 0.15 gCOD/g(TS)xd, aeration intensity of 800 dm(3) and constant activated sludge loading of 4 g/dm(3) were used in this system. The wastewater treated under these conditions satisfied the requirements of the Regulation of the Minister of the Environment of 8 July 2004 and could be discharged into receiving water.