Aims: (1) To detect the sterilization of flexible endoscope efficiency with ozone-producing machine IHI compared with Cidex OPA high disinfected solution (2) to remark the advantages and disadvantages of two sterilized methods. Objective and researching method: this is an intervention method, bacterial culture in the couple was done before and after sterilization of gastroscopes and colonoscopes with two disinfected methods. To detect the efficiency of sterilization: OZONE (59 samples) and Cidex OPA (75 samples). Results: effective intervention index of the sterilization with OZONE (94.6 percent), with Cidex OPA (85.1 percent). The sterilized method with Cidex OPA solution reduced bacterial density, the average result is 17.7 bacteria, it's lower as compared with OZONE (39.6 bacteria). The sterilization of OZONE system is good health for medical workel:s to disinfect the flexible endoscope directly, but it requires that medical center need to electrify, first investment capital. Operating cost with OZONE method is cheaper than Cidex OPA solution. Conclusions: Two disinfected methods have high efficiency of sterilization. However, ozone-producing machine is a safe method for medical workers, patients and it is friendly with environment. This method requires initial investment capital but it gives high comprehensive efficiency. It can be applied in all endoscopy centers in Vietnam.