Sterilization refers to physical and chemical processes that effectively kill whole microorganisms such as bacteria and fungi including spore forms and inactivate viruses. Effectiveness of various sterilization methods can be tested by different methods. The quality of sterilization can differ according to storage conditions and packing qualities in different health centers. The aim of this study was to determine the shelf-life of surgical equipment sterilized with different methods. Surgical equipment such as textile products, plastic and metal tools that are packed with textile cloth, metal (unwrapped) and paper used in surgical wards and operating rooms, at Uludag University Health Practice and Research Center, were investigated. These equipments were sterilized with ethylene oxide and PPSS (Prevacuum Pressure Steam Sterilization- Autoclaving) and shelf-lives of the sterilized were weekly and monthly investigated using microbiological methods. No microbiological growth was observed in materials packed with paper and sterilized with ethylene oxide gas in weekly and monthly controls. Microbiological growth was only observed with PPSS sterilization at the beginning of the 8th week. These growths were recorded in materials that are packed with paper and textile. Stenotrophomonas malthophilia, Staphylococcus warnei and Staphylococcus hominis were detected in metal equipment packed with paper, plastic materials packed with paper and textile material packed with paper, respectively. No growth was observed in materials packed in lidded metal boxes sterilized with PPSS. As a result of the study, it is suggested that ethylene oxide sterilization of paper packages is a safe and long-life method and the most important factors affecting shelf-life of the materials are type of package and method of sterilization.