Abstract Background: This study aimed to investigate the effects of addiction to computer games on physical and mental health of students. Methods: The study population includes all students in the second year of public guidance schools in the city of Isfahan in the educational year of 2009-2010. The sample size includes 564 students selected by multiple steps stratified sampling. Dependent variables include general health in dimensions of physical health, anxiety and sleeplessness and impaired social functioning. Data were collected using General Health Questionnaire (GHQ-28) scale and a questionnaire on addiction to computer games. Pearson's correlation coefficient and structural model were used for data analysis. Findings: There was a significant positive correlation between students' computer games addiction and their physical and mental health in dimensions of physical health, anxiety and sleeplessness There was a significant negative relationship between addictions to computer games and impaired social functioning. Conclusion: The results of this study are in agreement with the findings of other studies around the world. As the results show, addiction to computer games affects various dimensions of health and increases physical problems, anxiety and depression, while decreases social functioning disorder. Keywords: Addiction to computer games, Physical and mental health, Students of guidance school.