BACKGROUND Smartphone has greatly impacted education, health and social life. It has drastically changed the cultural norms and behaviour of individuals. 1 This study focuses on the usage patterns, accompanying behaviour and effects of smartphones among medical students. 2 They make it easy to stay in touch with people but their excessive use has raised concern, which might have negative impact on health and studies. Some of the hazards related to the smartphone use include headache, sleep disturbance, lack of concentration and impairment of short-term memory. 3 METHODS This cross-sectional study was conducted among the medical undergraduate students of Govt. Medical College, Nizamabad, Telangana State, during the period of October-December 2014 4,5,6. A convenient sample of 300 medical students was considered for this study. Participants were selected through simple random sampling and a pre-designed, semi-structured questionnaire was given to each student. 300 medical students were given pre-tested, pre-designed, semi-structured & self-administered questionnaire and the data regarding the usage patterns and effects of smart phone among the medical students of Nizamabad was collected. RESULTS Among the study subjects, the following results were obtained from our study, after analysis of data.  39.3% of them were using smartphone for more than 2 years.  96.7% of them feel that their knowledge improved.  22.6% of them were using smart phones for more than 6 hrs/day.  49.6% use them even after 11 P.M.  Social networking was the most used feature.  72.3% use them in classrooms. CONCLUSIONS The pattern of use differs between males and females. Usage for social networking is more among females. Usage after midnight and chatting with strangers is more prevalent among males. Behaviours like getting annoyed/restless when interrupted, are a point of concern. Factors like using the smartphone till late in the night might cause less sleep which might lead to less concentration in the classrooms. Also, the usage while in classroom is very high, this might also affect their concentration on studies. Symptoms like headache, eyestrain and stress were found in majority of the students after using the smartphone for a long time. All these factors might affect their concentration, academic performance and also their health in the long run. 3 In the existing scenario the need of the hour is to educate and create awareness among the students about the ill effects of over usage of smart phone, not only on their health but also on their studies and life style.