Objective: This study aimed to evaluate the relation between psychiatric diagnoses and internet usage in a clinical sample of adolescents and determine the pattern of internet use. Method: Adolescents aged 13-17 years who admitted to a child-adolescent psychiatry outpatient clinic for some emotional or behavioral problems were included. Psychopathologies were evaluated via clinicial interview and sociodemographic form and internet addiction scale were applied to be fulfilled. p <.05 was accepted to be significant for dual comparisons, p<.017 for triple and p<.012 for quadriple comparisons.. Results: TThere were 161 adolescents with 64% (n = 103) of all were girls. Internet usage and internet addiction scale variables pointed out that there was a relation between age, internet usage duration and internet addiction. Psychiatric diagnoses distribution was significantly higher among adolescents as 73.9% of all had at least one psychiatric disorder. Major depressive disorder was found to be significantly higher in addictive and risky groups. Discussion: Findings point out that there is a relation between internet addiction and psychiatric disorders especially major depressive disorder. These results could support the studies in this field as adolescents who have any psychiatric disorders ought to be evaluated for internet addiction.