Objective: Rapid development and prevalent use of smartphone, social networks, and the Internet variously affect the interactions, communications and health of the users. Hereupon, the objective of present study is to determine the overuse of smartphone and addiction to the Internet and social networks among the students of Kermanshah University of Medical Sciences in 2017. Materials and Methods: This descriptive analytical study was conducted in 2017. Firstly, 350 students from Kermanshah University of Medical Sciences were selected through a randomly clustered method as the sample size. Then the participants filled out the questionnaire about Internet addiction and overuse of smartphone and social networks. Finally, the data were analyzed by SPSS 19software and the results were presented in descriptive and analytical tables. Results: 321 questionnaires were completely filled out and they were handed over (91.7%). The mean score of Internet addiction was 40.05±20.69 while 19.6% of students did not have Internet addiction. The mild, moderate and severe Internet addictions were 48.6%, 24.6% and 7.2% respectively. Overuse of cellphone was determined51.96±18.55. Low, normal, and excessive uses of cell phone were respectively 9% ،75.4%and 15.6%. The addiction to social networks in cell phones of participants was 30.79±10.57. The rates of normal users, those who were exposed to the addiction and addicted users to social network were 36.4%, 53.9% and 9.7% respectively. There was a significant relationship between Internet and social networks addiction and overuse of smartphone (P = 0.001). Conclusion: Given the results of this study, students are exposed to the risks and complications of these technologies. Thus, it is essential to have some fruitful programs and strategies to promote students' knowledge and awareness about using the Internet, social networks and smartphone.