The principle of expediency can be found in the Convention on the Rights of the Child, which guarantees its application in the Croatian Juvenile Courts Act. International documents emphasize rights of the child, as well as the fast and ''painless'' implementation of procedures so as to protect all the rights regulated in those documents. In accordance with the principle of expediency, it is crucial to take the child's welfare into account in order to avoid negative effects of criminal procedures and juvenile prosecution processes. The principle of expediency is either conditional or unconditional. It is conducted by a prosecutor in preliminary procedures so as to avoid the stigmatization of a juvenile perpetrator. Avoiding labelling and stigmatization of juvenile criminal offenders is of great importance due to its evident negative effects on their further behaviour. The minimum age of criminal responsibility differs from country to country; in Croatia the minimum age of criminal responsibility is 14. This thesis problematizes the introduction of the doctrines doli incapax and discernimenta in the Croatian juvenile justice system, the purpose of which is to prevent juveniles from commiting crimes. Risk factors such as juveniles' personal characteristics, family relationships, school, peers, stand as strong predictors of juvenile delinquency.