Periodontological grafts are materials used in dentistry to regenerate lost gingival soft tissues or bone parts. In the case of direct contact with blood, the possibility of disease transmission from the source to the patient is high. This source can be an animal or a human. Therefore, the sterilization of grafts before implanting to the patient is of significant importance. The purpose of this study was to evaluate gamma radiation and microwave sterilization processes from microbiological and sterility perspectives and to compare the effectiveness of these two sterilization methods. Grafts were irradiated with 2, 4, 5, 10, 25 and 50 kGy doses of gamma radiation. Another group of same materials was irradiated by microwave for 1, 2, 3 and 4 min at 24,500 MHz and 900 W. Gamma radiation and microwave sterilization methods were evaluated as successful at minimum doses as 5 kGy and 3 min, respectively. Both gamma and microwave sterilization successfu lly sterilized periodontological grafts coded as PBG1, HBG1, HL1, PDG1, MBG3, MDG2 and PDG3. Moreover, microwave sterilization can be used as an alternative novel method to gamma radiation sterilization.