Background: The purpose of this study was to determine changes in sole arch index and their effects on non-contact lower-extremity injury rates among male karateka. Materials and Methods: forty-five male karateka with knee or ankle injuries were chosen from 288 male athletes attending 6 athletic clubs in Kerman-Iran. Injury-related data were collected via a data recording sheet and sole arch index was measured through Chippaux-Smirak Index (CSI) method. T-Student and Chi-square tests were used for statistical analysis of data. Results: The study’s results showed that the most frequent location and time of injury were respectively in knee joint (62.2%) and during training sessions (82.3%). the severity of injuries was minor (57.8%) in most cases. Moreover, sole arch index in right leg was abnormal in 68/9% of subjects while 31.1% of them had a normal index in that leg. When left leg was concerned, abnormal and normal indices was evident in 77.8% and 22.2% of subjects respectively. In general, highest percentage of abnormal sole arch index was found in left leg (77.8%). statistical analysis of data by Chi-square test demonstrated that there is no relationship between sole arch index in right and left legs. Again, application of Chi-square test to obtained data showed that there is no relationship between sole arch index and severity of injury. In addition, statistical data analysis through t-test was indicated that there is a significant difference between noncontact lower extremity injury rates when sole arch index is considered (p>0.05). Conclusion: According to the results of this study, abnormal sole arch index may significantly affect non-contact lower-extremity injury rates in male karate athletes. Key Words: Non-contact Injury Mechanism, Deformity, sole arch index, CSI Method.