An important minority of people, those who are internet users, develop a pathological passion towards it, named „internet-addiction”. This is a new concept for psychiatric science, it’s neither met in ICD-10, nor in DSM-IV. The preliminary data is important for elucidating predisposing factors and the psychosocial versions of treatment methods. Experts enrolled in mental health field should have knowledge about internet-addiction that would allow them to diagnose it from the beginning and to use specific ways of treatment. In the paper given below there are elucidated some general notions about the causes, diagnosis and possible methods of treatment of internet-addiction.