Background and Objective: Internet has been an essential component in daily life of people all over the world. However,the outgrowth of the internet-addictive behaviours in developing countries like India,especially among students is a serious threat to the social well-being. The present study intends to estimate the prevalence of internet addiction among engineering students of Tamil Nadu,based on demographic factors and to analyse its effect on parameters of academic performance: time spent on education,attention in class and academic grades obtained by the students. Methods: A cross-sectional online survey was conducted on engineering students in Tamil Nadu. Data was analyzed statistically using Two-sample t-test at a significance level of 0.05 (5%). 35 % of the respondents were found to be internet-addicted and the prevalence was more among male students (39.2%) than females (23.1%). Results: Results showed that there is a significant effect of internet addiction on students’ attention in class but not on the time spent on education and academic grades obtained by the students. Conclusion: The high prevalence of internet addiction among students in India is already a public mental health problem. There is a need for responsible actions by the administrators of educational Institutions to create awareness among students and to avert students from getting distracted due to unproductive internet activities. © 2016,International Journal of Pharmacy and Technology. All rights reserved.