Abstract Ethylene Oxide (EtO) sterilization is the most common method that effectively sterilizes many types of medical equipment, especially those that are heat-sensitive, made from certain polymers, or with long lumens. However, EtO systems suffer from the long sterilization time, high cost, the high toxicity of EtO, and negative environmental impacts. As a promising alternative, hydrogen peroxide gas plasma (HPGP) sterilization eliminates most of the above disadvantages, but the HPGP cannot sterilize narrow or long lumens of medical scopes due to the suppressed gas diffusion deep inside the lumen, limiting its potential to completely replace EtO. In addition, HPGP sterilization may fail if a thorough drying and careful loading of the equipment were not performed. To develop an equivalent or improved solution to EtO while retaining the advantages of HPGP, Advanced Cooling Technologies, Inc. (ACT), in collaboration with Rutgers University (RU), proposes an ozone plasma sterilization system with plasma-in-lumen technology. The system uses air to generate plasma containing strong sterilizing agents such as ozone (O3) and hydroxyl radicals at near-atmospheric pressure. The plasma is generated inside a sterilization pouch that is made from reusable and flexible sheet plasma generators to reduce sterilization time and system weight. Additionally, the system has an innovative thin-tubing plasma generator that can be directly inserted into the long lumens of surgical scopes to supply ozone, fundamentally eliminating the lumen length limits of the current HPGP systems. The system will accommodate multiple pouches at once to increase sterilization throughput. Further, the ozone sterilization can operate without thorough drying, and the insulation layer on the sheet plasma generator can eliminate failure due to improper loading.