Java medaka ($Oryzias$ $javanicus$) cDNA array was constructed and the microarray platform was used to compare the hepatic expression profiles of Java medaka fish exposed to $17{eta}$-estradiol with those of unexposed controls. Data analysis demonstrated that the expression profiles were strongly affected by $17{eta}$-estradiol exposure, with 655 genes up- or downregulated after 24 h, and 633 genes after 48 h. The differentially expressed genes were analyzed to determine the effects of $17{eta}$-estradiol exposure on the liver tissue and were classified into five functional categories: information storage and processing, cellular processes and signaling, metabolism, general function prediction only, and function unknown. Genes whose expression was upregulated more than 10-fold were predominantly associated with energy production/conversion and reproduction, and 30% of the genes whose expression was downregulated more than 10-fold were associated with carbohydrate transport and metabolism. The observed differences in the expression profiles of 7 genes (encoding apolipoprotein B, cytochrome P450 1A, glucose-6-phosphate dehydrogenase, glutamate dehydrogenase 1b, vitellogenin, selenoprotein M, and transferrin) were confirmed by quantitative RT-PCR, and their transcriptional changes in the livers of Java medaka induced by exposure to 10, 100, and $1000{mu}g$/L $17{eta}$-estradiol were investigated. These results should allow the development of biomarkers for the identification of $17{eta}$-estradiol contamination in the environment and provide molecular biological information on the effects of endocrine-disrupting chemical exposure on marine animals.