A large number (N 50 569) of 14-16 year old Finnish adolescents taking part in the School Health Promotion Study were surveyed for delinquent behaviour in relation to depression. The results indicate a robust association between delinquency and depression. Among girls risk for depression varied between 1.3 and 3.1 according to various antisocial behaviours (the equivalent risk among boys was 1.3-2.5). Depression increased according to the frequency of delinquent behaviour. The results emphasize the importance of comprehensive clinical assessment and treatment of delinquent adolescents.