Overuse of the Internet has significant impact on human life by causing psychological and social problems. This study is an attempt to describe the prevalence of addictive Internet use and mental health status among students in a public university in Iran. The relationship between Internet use and socio-demographic as well as mental health dimensions was explored. Methods: The present study relied on a cross-sectional design and 400 students were selected through proportional stratified random sampling. The data were collected using validated and reliable scales, Young Internet Addiction Test (YIAT) and Goldberg General Health Questionnaire (GHQ-28). Descriptive statistics, Independent Sample t-test, Chi- square test, and Binary Logistic Regression were conducted for data analysis. Results: The mean age of participants was 22.06. The overall prevalence of Internet addiction among the students was 34.5%. Logistic regression analysis indicated that the age of starting Internet use [OR: 0.92, 95% CI: 0.87,0.99; p=0.028], daily time spent on the Internet [OR: 1.12, 95% CI: 1.05,1.21; p <0.0001], purpose of Internet use [OR: 3.32, 95% CI: 2.08,5.48; p <0.0001] and anxiety/insomnia [OR: 1.20, 95% CI: 1.07,1.28; p <0.0001] are the significant predictors of Internet addiction. Conclusion: The Internet addiction among the students was high. The purpose of Internet use, experiencing a higher level of anxiety/insomnia, surfing on the Internet for long time are related to the Internet addiction. Organizing cognitive behavioral intervention programs may be effective in developing self-regulation skills of students in order to control their Internet use.