Abstract: The present study has been made on the existance on the fish fauna and non-fin fishes in the River Atrai of Naogaon district. The study area is located on the Eastern bank of the River Atrai and it includes the Chotkighasa to Casiabari hat under Atrai thana near the Naogaon town. Data were collected from the local place and monthly visits were made in the fish markets of Ahsangong and Casiabari hats during the study period. Visits to the fish-landing centers of Atrai station, Kumghat, Shahebgong and Chotkighasa areas were also made almost once in a week throughout the study period starting from August, 2005 to July, 2006. During the study period, a total number of 78 species of fishes belonging to 48 genera, 19 families, 9 orders and the class of osteichthyes, 11 species of non-fin fishes under the classes of Crustacea (Arthropoda), Gastropoda (Mollusca), Amphibia, Reptilia were detected and recorded.