The lchthyofauna was investigated at the nine sites in the Tam-jin River from September 10, 1990 to October 12, 1993. The fishes were collected by means of a casting net and hooks. The collected fishes were classified into 34 species of 26 genera in 13 families. In the present study 3species of Acanthogobius hasta, Macropodus chinensis and Channa argus were newly collected. Among the 34 species, 12 were known to be endemic species in korean waters they are Rhodeus uyekii, Acheilognathus yamatsutae, Acanthorhodeus gracilis, Sarcocheilichtys variegatus wakiyae, Squalidus chankaensis tsuchigae, Squalidus japonicus, Squalidus gracilis, Microphysogobio yaluensis, Cobitis longicorpus, Pseudobagrus koreanus, Liobagrus mediadiposalis, Odontobutis platycephala. The dominant species were Zacco platypus, Zacco temmincki and Acheilognathus yamatsutae.