Environmental stress dramatically induces stress responsiveness in an organism and it affects its related genes expressions. We obtained six stress-responsive genes [metallothionein (MT), catalase(CAT), superoxide dismutase (SOD), glutathion S-transferase (GST), cytochrome P450 (CYP1A), ubiquitin (UB)] from Oryzias javanicus and investigated their expression changes in fishes exposed to a variety of concentrations of cadmium. We designed PCR primers for the stress responsive genes from highly conserved region in various organisms and have cloned by reverse transcription polymerase chain reaction (RT-PCR). The fishes (n=5, respectively) were exposed to various concentrations of cadmium for 24 hr then total RNAs were extracted from livers. The levels of CYP1A1, MT, SOD, and UBI transcripts were elevated in all Cd-exposed fishes comparing to non-exposed control in a dose-dependent manner. However, CAT and GST gene expression were increased in 0.1 and 10 ppb of Cd-exposure and drastically decreased in 1000 ppb of Cd-exposure. This study provided the basic gene expression profiles by heavy metal stress and those genes could be used as biomarkers to assess the marine environmental pollution.