The article is devoted to the analysis of the judicial practice of the Supreme Court regarding criminal liability for non-performance or improper performance of official duties by a doctor, clarification of the main reasons that contribute to the commission of this crime and ways to prevent them, determination in which categories of medical professions this offense is most often committed, monitoring legislative framework regulating the activities of medical workers. Within the framework of this article, the decisions of the Criminal Court of Cassation as part of the Supreme Court (CCC) was studied, which set out the legal positions of the court of cassation regarding prosecution for the improper performance of professional duties of doctors. The question of the responsibility of doctors for the improper performance of professional duties is very complex, since the activity of providing medical services quite often carries the risk of adverse treatment results for the patient, in the form of unavoidable consequences. In many cases, a doctor who respectfully fulfills his professional duties makes everything possible, but for reasons beyond his control, he is unable to prevent harm to the patient's health. In such a case, the medical worker is not held liable, even in the event of the patient's death. However, in some cases, studies that are difficult for the patient's health or his death cannot be avoided, and their occurrence is connected with the doctor's non-fulfillment or improper fulfillment of his professional duties. Non-fulfilment of professional duties means that a medical or pharmaceutical worker does not perform those actions that he is obliged to perform by virtue of the work performed. Non-fulfilment or improper fulfillment of professional duties by the relevant entity can be both one-time and systematic. Since the disposition of article 140 of the Criminal Code of Ukraine has a blanket character, in each specific case it must be established which professional duties were entrusted to the guilty person and which of these duties were not performed at all or performed improperly, as well as the requirements of which specific regulatory acts (instructions, rules, instructions etc.) violated by the offender. In each specific case, in order to prove the guilt of a medical or pharmaceutical worker, it must be established which professional duties were entrusted to the guilty person and were not performed at all, which is the absolute inaction of a medical worker under a real opportunity to act, and which of such duties are improper performed, i.e. medical workers perform their professional duties, but with significant violations of direct duties, which are regulated by job instructions, qualification requirements and treatment protocols with a clear algorithm of actions, orders and instructions of the Ministry of Health and SES of Ukraine, WHO recommendations. Key words: improper performance of professional duties by a doctor, medical assistance, medical documentation, professional activity, childbirth, criminal negligence, death, grave consequences, criminal liability.