A survey was conducted on ichthyofauna diversity at two sampling sites in Torsa River, North Bengal, West Bengal, India from February 2014 to March 2016 with the help of professional fishermen. A total number of 131 fish species under 11 orders, belonging to 29 families and 70 genera were reported. Families of Cyprinidae, Sisoridae, and Bagridae were the most dominant. Catch per unit effort, the number of fish genera, evenness index, Shannon diversity index, Margalef's richness index, and dominance index ranged from 36-110 individuals/100m² (SD±18.00), 33 to 64 (SD±7.83), 3.06 to 6.56 (SD±0.45), 0.973 to 0.996 (SD±0.004), 8.22 to 13.4 (SD±1.25) and 0.018 to 0.87 (SD±0.009), respectively. Maximum seasonal variation of CPUE, number of fish genera, Shannon diversity index, and Margalef's richness index were recorded in the rainy season while reaching their minimum values in winter. Out of 131 fish species, 7.63% were assigned a threatened category (IUCN category).