Background: Students read with mobiles, revise with mobiles, romance with mobiles, rejuvenate with mobiles and thus getting restricted to mobiles. It is integrated into the core activities of daily living. College students use internet for social communication as much as they use for education. Medical students need to study throughout their course for longer hours compared to other streams. This study was conducted with an objective to assess the prevalence of phone dependence, associated disturbances and its awareness among medical students in Chennai. Aim and objective: To estimate the prevalence of mobile phone dependence, and its impact among medical students in Chennai. Materials and methods: A cross sectional study conducted among 621 medical students in government colleges of Chennai from August 2017 to January 2018.Data were collected through a semi structured questionnaire and analysed using SPSS version 16. Results: The prevalence of mobile phone dependence among medical students in Chennai was 66.66%.68.14% of male were dependent on mobile phones.64.84% of females were dependent on mobile phones. The prevalence of nomophobia among study participants was 15.62%. Conclusion: Health education about the harmful aspects of mobile phones should be promoted. Encouraging students and providing opportunities for participating in physical activities and other recreations rather than spending their leisure hours in mobile phones. Awareness to parents about the psychological effects of mobile phones so that parental supervision increases.