In this master thesis, the topic is the legal description and analysis of the criminal offense of medical malpractice, showing also court practice. The criminal offense of negligent treatment is described in Article 181 of the Criminal Code and is included in the criminal offense against human health in Chapter XIX. Given that it is a criminal offense that has received a lot of media coverage and that an image of the health care system is created through this criminal offense, this paper displays cases that stood out the most and influenced public opinion. The first part of the paper begins with a historical overview, followed by the presentation of the models of criminalization of negligent treatment in the world and their disadvantages and advantages. Furthermore, the paper analyzes and defines all the terms and elements that make up the criminal offense of medical malpractice through the legal definition, especially emphasizing the perpetrators of the crime, causation, negligence, consent, and exclusion of unlawfulness. At the end of the paper, the judgments of the European Court of Human Rights, including one against the Republic of Croatia, and judicial practice in the Republic of Croatia, with an emphasis on the role of experts in the proceedings, are presented. Finally, the statistical presentation of this criminal offense in the period from 2016 to 2021 is presented.