Background: Although problematic Internet use (PIU) is a growing problem among adolescents, few studies have examined its prevalence among university students in Iran. This study was designed to investigate the prevalence of PIU and its potential risk factors among students at Kerman University of Medical Sciences, Kerman, Iran. Methods: In a cross-sectional study, data was collected from 976 university students. PIU was assessed by the 18-item Problematic Internet Use Questionnaire. In addition, information on demographics and Internet usage pattern was also collected. Findings: A total of 920 students completed the survey (response rate = 94.8%). Of them, 98% were Internet users. Overall, 21% of the students were identified as problematic Internet users. Logistic regression analysis showed that spending more time online, having a history of psychiatric disorders, and using the Internet for chatting and playing games were risk factors for PIU. Conclusion: PIU is a common problem among university students. These results suggest the need for preventive and interventional strategies for this vulnerable group.Keywords: Problematic Internet use, University students, Iran.