BackgroundFacebook is a social networking service launched in February 2004, owned and operated by Facebook, Inc. As of June 2012, Facebook reports more than 1 billion active users. Objective of study was to evaluate the effect of Facebook on the social life, health and behavior of medical students.MethodologyIt was a cross sectional, observational and questionnaire based study conducted in Dow University OF Health Sciences during the period of January 2012 to November 2012. We attempted to interview all the participants who could be approached during the period of the study. Participants were MBBS students, while all students of other courses and programs were taken as exclusion criteria. Approximately 1050 questionnaires were distributed to participants. Fifty questionnaires were rejected due to incomplete answers, yielding 1000 usable responses for an approximate 95% response rate. Informed verbal consent was taken from each participant. Study was ethically approved by Institutional Review Board of Dow University of Health Sciences. All the data was entered and analyzed through SPSS 19.ResultOut of total 1000 participants, males were 400 (40%) and females were 600 (60%). Participants were in the age group of 18–25 years with a mean age of 20.08 years. Most of the participants were using Facebook daily (N = 640, 64%) for around 3–4 hours (N = 401, 40.1%). Majority of them (N = 359, 35.9%) believed that they were equally active on Facebook and in real life while few believed their social life became worse after start using Facebook (N = 372, 37.2%). Most of the participants admitted that they were considered as shy in real world (N = 390, 39.0%) while in the world of Facebook they were considered as fun loving by their friends (N = 603, 60.3%). A large number of participants (N = 715, 75%) complained of mood swings.ConclusionYoungsters are willing to compromise their health, social life, studies for the sake of fun and entertainment or whatever satisfaction they get after using Facebook. What we observed in our study was that although majority of our subjects showed multiple signs of Facebook addiction, they don’t realize it and if even they realize it they don’t want to quit Facebook and even if they want to quit, they can’t. Our observance concluded that majority of the users are highly addicted.