The relationships between aggression and both hereditary and social factors are still very unclear. To examine the interrelations between aggression, temperament and character dimensions and parental rearing factors, 188 delinquent adolescents and 118 same-aged schoolchildren from north-western Russia were studied by means of the Buss-Durkee Hostility Inventory, Temperament and Character Inventory (TCI) and EMBU questionnaire on parental rearing. Delinquent adolescents differed significantly from non- delinquents on the majority of variables under investigation. Overt aggression was most strongly related with novelty seeking, whereas covert aggression was related with harm avoidance. Furthermore, the aggression scores were related to lack of paternal emotional warmth. Our results point to the significant role of both temperament characteristics and parental rearing as background factors in the development of aggression among adolescents.