Objective To establish a tetracycline-dependent regulation of SV40 Tag transgenic mice.Methods\ p205-sv40Ta p205-rtTA-C3 and pTRE-Tag dual transgenic mice was generated by pro-nuclear microinjection and embryo transplantation.Positive founder mice were identified through both PCR and Southern blot.Results\ A rtTA and Tag dual positive transgenic mice,two rtTA single and one Tag single transgenic mice were confirmed by PCR and Southern Blot.The expression of Tag mRNA was detected by RT-PCR in the ovary of the dual transgenic mice which were administered with tetracycline in the drinking water.Conclusion\ The results of this study indicate that it is possible to establish a tetracycline-dependent regulation of SV40 Tag transgenic mice by administeration of tetracycline in the drinking water.