Internet addiction, a relatively new phenomenon, is a field of recent research in mental health, particularly within young populations. It seems to interact with several individual and environmental factors.We aim to spot internet addiction in a Tunisian adolescent population, and to study its relationship with personal and family factors, as well as with anxious and depressive comorbidities.We conducted a cross-sectional study of 253 adolescents recruited in public places in the city of Sfax in the south of Tunisia. We collected biographical and personal data as well as data describing family dynamics. The internet addiction was assessed by Young's questionnaire. Depressive and anxious co-morbidities were assessed using the HADS scale. The comparative study was based on the chi-square test and the Student's test, with a significance level of 5 %.The prevalence of internet addiction was 43.9 %. The average age of internet-addicts was 16.34 years, the male sex was the most represented (54.1 %) and increased the risk of internet addiction (OR a=2.805). The average duration of connection among Internet addicts was 4.6hours per day and was significantly related to internet addiction; P<0.001). Socializing activities were found in the majority of the internet-addicted adolescents (86.5 %). The type of online activity was significantly associated with internet addiction (P=0.03 and OR a=3.256). Other behavioral addictions were frequently reported: 35.13% for excessive use of video games and 43.25 % for pathological purchases. These two behaviors were significantly associated with internet addiction (with respectively P=0.001 and P=0.002 with OR=3.283). The internet-addicted adolescents lived with both parents in 91.9 % of cases. The mother's regular professional activity was significantly associated with internet addiction risk (P=0.04) as was the use of the Internet by parents and siblings (with respectively P=0.002 and P<0.001 with OR=3.256). The restrictive attitude of the parents was significantly associated with internet addiction risk (P<0.001 OR=2.57). Family dynamics, particularly at the level of adolescent-parent interactions, were a determining factor in internet addiction. Anxiety was more frequently found than depression among our cyber-dependent adolescents with frequencies of 65.8 % and 18.9 %, respectively. Anxiety was significantly correlated with the risk of internet addiction (P=0.003, OR a=2.15). There was no significant correlation between depression and the risk of internet addiction.The Tunisian adolescent seems at great risk of internet addiction. Targeted action on modifiable factors, especially those affecting family interactions, would be very useful in prevention.