Objectives: The aim of the current study was to assess the psychometric properties of Online Game Addiction Inventory in under graduate students of Shahid Chamran University of Ahwaz. Method: Of all under graduate students in Shahid Chamran University of Ahwaz during 2014-15 academic year, 300 under graduate students from Shahid Chamran University were selected using multistage random sampling method. Samples completed Online Game Addiction Inventory and Young Internet Addiction Inventory. Cronbach’s alpha was used for examining the internal consistency of Online Game Addiction Inventory. The study tool was validated using construct, criterion and convergent validity. Results: Cronbach’s alpha was calculated 0.95 for this inventory under study. Construct validity confirmed and principal component analysis with Varimax rotation identified two factors, namely, ethical and mood problems and education and employment problems, respectively. These two factors accounted for 57% of the total variance. Independent t-test results revealed significant difference on the mean scores of online game addiction between the two addicted and normal groups. The results showed a significant difference in a rate of online game addiction between two groups. Convergent validity was tested by administration of Online Game Addiction Inventory and Young Internet Addiction Inventory concurrently; correlation coefficient was obtained 0.7. Conclusion: Current study results showed appropriate psychometric features of Online Game Addiction Inventory. Therefore, it can be used for examining online game addiction in Iran.