Background: Today, the prevalence of Internet Addiction (IA) is increasing among college students and the mental health of students is reduced with the increasing severity of IA. Objectives: The aim of this study was to evaluate IA and mental health among medical sciences students in the southeast of Iran. Materials and Methods: This cross-sectional study was carried out on 417 students of Zahedan University of Medical Sciences, Zahedan, Southeast of Iran, during year 2016. The participants were recruited through a two-stage stratified sampling method. The data collection was done using Young Internet Addiction Test (YIAT) and Goldberg General Health (GHQ) standard questionnaires. Data analysis were performed by ANOVA, Pearson correlation, chi-square, and logistic regression tests using SPSS software for Windows version 16. Results: The overall prevalence of IA in students was 27.56% (95% CI: 21.3 to 30.8). The prevalence of IA was 15.82% (95% CI: 11.3 to