The "Centros de Atenção Psicossocial Infanto-Juvenil" are dispositives of treatment for children and adolescents suffering from severe mental disorders. This article describes sociodemografic characteristics of users of those centers between September 2008 and February 2009 in the state of São Paulo, Brazil. Data from active files randomly selected was collected in 19 Centers in the state of São Paulo. The characteristics analyzed were divided in four groups of variables: identity; living conditions; family structure; schooling and occupation. The results indicated a higher concentration of users between 10 to 14 years-old; prevalence of males; tendency to nuclear and reduced family arrangements (45%); care primarily given by the mother (57%) and high frequency of users attending the regular school (86%). It was possible to identify a well-defined socio demographic profile of users, with differences regarding gender, attending the regular school and/or other institutions, as well as sharing a nuclear family arrangement.