Aim: Computer and internet have become an indispensable part of our lives. As information and communication is improving very fast day by day. The purpose of the current study is to determine internet addiction levels of adolescents aged between 11 and 18 years. Methods: This study design descriptive. The population of the study was comprised of adolescents who are hospitalized at pediatric clinic of training and research hospital between November 2017 and January 2018 in Istanbul. The adolescence (N=123) who were voluntary and complying with the sampling criteria participated to the study. Sampling was determined using various criteria. Socio-demographic form and Internet Addiction Scale were used as data collection tools. Results: The mean score of internet addiction scale was 66.54±21.63. Age of group no internet addiction (r=0.320; p<0.01), mobile phone daily usage time (0.263; p<0.05) and internet weekly usage time (r=0.235; p<0.05) variables there was a positive and significant correlation with addiction score. On the other hand, there was a positive and significant relationship between internet daily usage times (r=0.406; p<0.01) internet weekly usage time (r=0.314; p<0.05) and addiction scores. Conclusion: It was determined that internet use is a problem within the limits of universal life and it affects young groups especially as adults of the future. Herewith, it was determined that the internet use was a problem within the limits of universal life and it affects young groups especially as adults of the future. Hospital internet use is as common as the internet used in social environments.