In the present report an attempt has been made to provide information on species diversity of fish fauna collected from Mayurakshi River in Birbhum district along with their abundance, IUCN status and seasonal variation. Result reveals the existence of 80 species belonging to 23 families under 10 orders of which 3 are recently discovered new species. The most diverse family is Cyprinidae with 30 species and 16 genera. Ichthyofaunal diversity of Mayurakshi River is maximum compared to other eight major rivers of South Bengal. Maximum number of species and families are available in Monsoon and Post-monsoon period while in winter and summer, the number is minimum. Bray-Curtis dissimilarity index is minimum within the season while maximum in between two seasons either summer-monsoon or monsoon-winter.