Criminology and criminal law are two separate scientific disciplines which are mutually helpful for each other. Criminology is a practical discipline whose most important scientific method is empirical method relying solely on the statement of facts which makes it neutral from judgements and assessments. Criminal law, in turn, belongs to the category of normative sciences where the fundamental method is the legal-dogmatic method. The law is based assessment because the values adopted by law are the foundations on which moral and public order are built. As criminology and criminal law possess common research areas, criminology can serve as an auxiliary discipline for criminal law and was treated as such already at the dawn of its existence in the 19th century when it was believed that empirical sciences were to reform and improve social reality. Criminology derives from criminal law legal definitions pertaining to types of crimes and referring to their legal shape, whereas the legislation of criminal law which is grounded in reality and evolution judicature both require knowledge of criminology. Outcomes of criminological research are used for the purposes of criminal law which creates a bond between these two disciplines and this bond which supports their mutual co-existence.