We investigated the fish fauna of the Kita River flowing through Miyazaki Prefecture during 2000 and 2007. The fish fauna of the river has 165 species belonging to 59 families. The Kita River is considered to be one of rivers with the largest diversity of the fish fauna in Japan. Being divided into eight groups of their life cycles, fishes living in the tidally influenced areas occupied a large proportion （88 species）, while genuine freshwater fishes were scarce （18 species）. The largest diversity of the fish fauna in the Kita River is thought to reflect a wide spatiality and a large diversity of variable environments in the tidally influenced areas. The fishes having a southern distribution such as in the Ryukyu Islands occurred frequently. These results would contribute to clarify the fish fauna of rivers around Miyazaki Prefecture.