Over the past two decades, internet use has been increased significantly worldwide. The present study aims at examining the associations between internet use in emerging adulthood and crucial developmental dimensions during this age period, namely life satisfaction, identity development, and attachment style. Previous studies have shown that there is a high risk of excessive internet use during emerging adulthood. Five hundred men and women aged 18 to 25 years participated in the study. They completed (a) The Internet Addiction Test (Young, 1998), (b) The Life Satisfaction Scale (Diener et al.,, 1985), (c) The Dimensions of Identity Development Scale (Luyckx et al., 2008), and (d) The Relationship Scales Questionnaire (Griffin & Bartholomew, 1994). Hours of daily use, specific online activities and socio-demographic variables were also assessed. The results of the research showed that the excessive use of the internet is significantly related to hours of daily use and to specific online activities. Men made significantly more use of the internet than women. Those who were not satisfied with their current life conditions, were engaged in exploration in breadth, ruminative exploration and avoided or felt uncomfortable with close interpersonal relationships, were more likely to resort to excessive internet use. These results have implications for future studies regarding excessive internet use in relation to young people’s quality of life.