Background: The internet itself is a harmless technology. However, its overuse and misuse will expose its users to internet addiction. On the other hand, diagnosis of students’mental dysfunction is of prime importance, and their progress and academic success in the future can be prevented by this technology if not properly handled. Methods: In this descriptive and correlational study, the statistical population consisted of all students at Kermanshah University of Medical Sciences, of which 447 students studying in the first and second semesters of the academic year 2017-18 were selected through Cochran's Sample Size Formula and Stratified Random Sampling. As for data collection, the Young's Internet addiction Test (IAT) and Goldberg General Health Questionnaire (GHQ-28) were utilized. Moreover, for data analysis, the descriptive statistics (percentage, mean, standard deviation) and inferential statistics (T-test, Pearson correlation coefficient, and multiple regression analysis) were employed in the environment of SPSS Statistical Software Version 23.0. Results: The results of the present study demonstrated that the total mean score of students’ internet addiction and mental health measured 3.81±0.88 and 2.56±0.33, respectively. The results also indicated that internet addiction correlared positively with depression whereas negatively with mental health (P<0.001). Besides, the results of multiple regression analysis revealed that the five major predictors of vulnerability to internet addictionin university students were as follows: the key reason for using the internet, faculty, depression, the main place for using the internet, and somatic symptoms. Conclusions: According to the findings of the present study, it can be concluded that students’ excessive use of the internet leads to depression, anxiety, and reduced mental health, thereby affecting their academic performance. Hence, it is suggested that further monitoring and control be exercised on how the internet is used by university students, and they should be informed of the detrimental effects of this technology in the case of misuse or overuse.