Experiments were carried out with the preparation Nilsan (oxiclozanide + levamizal) in the treatment of sheep with Fasciola, Dictyocaulus, and Trichostrongylus infection. The trials involved a total of 2782 sheep on two sheep-breeding farms, constituting 15 flocks. The liveweight of the adult animals ranged from 40 to 60 kg, and that of the year-old female ones--from 40 to 45 kg. The daily ration on the two farms did not differ essentially from that offered to the animals in the past 2-3 years. It was found that at the rate of 22 to 28 cm3 per head Nilsan produced 76.67 to 96.67 percent effect against Paramphistomum infection, 100 percent effect against Dictyocaulus infection, 73.37 to 90.00 percent effect against Trichostrongylus infection, and 23.34 to 83.34 percent effect against Dicrocelium infection. The application of an ex tempore combination of oxiclozanide and levamizal to sheep at the rate of 24 cm3 per head produced 86.67 to 100 percent effect against Paramphistomum, 96.67 to 100 percent effect against Dictyocaulus, 86.67 to 96.67 percent effect against Trichostrongylus, and 46.67 to 86.67 percent effect against Dicrocelium. The experimental sheep produced 16.41 to 37.40 per cent more wool, 0.85 to 35.09 per cent more milk, and 8 to 12 per cent more weight gain.