Master's thesis The Criminal Offence of Aggravated Murder in the Practice of the County Court of Varaždin shows qualified forms of the crime of murder in Croatian legislation as well as in case law. At the beginning of the paper, there is an overview of the occurrence of the crime of aggravated murder through the headlines of contemporary media. The attention of scientists and the research they conduct significantly contribute to the progress of the criminal justice framework of aggravated murder. The chapter on the criminal protection of the right to life is focused on the right to life as one of the fundamental human rights and values. Croatian criminal law has been greatly amended by the new Criminal Code, and the paper lists significant changes related to the criminal regulation of the criminal offense of aggravated murder. The following chapter of the paper presents theoretical conclusions about certain forms of the aggravated murder. The following is an overview of the phenomenological aspects of aggravated murders in the Republic of Croatia in the five-year period from 2017 to 2021. A special chapter is dedicated to the legal research conducted at the County Court of Varaždin. The legal research includes an analysis of the court's four final verdicts finding the perpetrators guilty of committing the crime of aggravated murder and one verdict in which the Court established that a mentally incompetent defendant has committed an illegal act.