In an effort to develop the viomarker for monitoring the contamination of xenoestogen in the freshwater environment of Korea, reverse transcription-polymerase chain reaction (RT-PCR) analysis of vitellogenin(VTG) gene expression was optimized in Hemibarbus labeo. Based on the homology of the VTG cDNA sequences between the common carp and zebra fish, a set of PCR primers for VTG m RNA amplification for H. labeo was designed. VTG mRNA level in livers in livers from female and male fishes was analyzed by RT-PCR following single injection of 17 beta estradiol(E₂10㎎ ㎏^(-1)B.W.).As an internal control, beta actin mRNA was amplified. One ug of total liver RNA was subjected to RT-PCR. In female the amount of PCR product of VTG gradually icreased in the range from 16 to 34 cycles of amplification. On the contrary, in control male, PCR product first detected at 32 cycles of amplification and linearly increased up to 40 cycles of amplification. In E₂injected male liver,the VTG mRNA level was similar to that in the female. Taken together, this result suggests that liver of male H. labeo expresses minute amount of VTG mRNA which are 2^(-16)equivalent of female and that induction of VTG mRNA occurs in male liver after estrogen treatment. In conclusion, the optimized protocol for RT-PCR analysis of VTG mRNA expression in liver of male H. labeo will provide the environmental monitoring method for the xenoestrogen contamination in the rivers in Korea.