Bio-efficacy of a new fungicide, Lustre 37.5 SE, a combination of Flusilazole (12.5%) and Carbendazim (25%) was evaluated alongwith Propiconazole, Hexaconazole and Thiafluzamide against the sheath blight of rice at Rice Research Station, Chinsurah, West Bengal under filed conditions during the kharif season of 2008. A highly susceptible cultivar, Swarna, was used in the experiment. The plants were inoculated with highly virulent isolate of the fungus, Rhizoctonia solani Kuhn. The mean disease severity observed after two sprays at 10 days interval revealed that the best results were obtained through application of Lustre 37.5 SE having minimum disease incidence of only 38.3 per cent. The other treatments, namely Propiconazole, Hexaconazole and Thiafluzamide had 49.9, 51.8 and 59.7 per cent disease incidence, respectively. Lustre 37.5 SE also proved to be the best treatment for giving the highest yield of 4.06 t/ha, while Thiafluzamide, Propiconazole and Hexaconazole treated plots could produce only 2.90, 3.10 and 3.13 t/ha, respectively. Thus, with minimum disease incidence and highest yield /ha, Lustre 37.5 SE proved as the best treatment among all the tested fungicides.