Introduction. Adverse events (AE) in the process of pharmacotherapy can have direct consequences on the health and life of a patient. Factors leading to AE are categorized in human and systematic ones. Among the latter ones, the most important are significant shortages of nursing staff as well as stress, fatigue and the Occupational Burnout Syndrome. Reporting of AE is a crucial pillar of prevention of adverse events in drug administration in nursing.
 Aim. The aim of the study was to identify and analyse the factors leading to adverse events in the pharmocotherapy process and to present methods of prevention AE.
 Material and Methods. The research was lead among 100 hospital nurses from Pomeranian region. A research and research questionnaire was based on the study “Attitudes and beliefs of health services about the causes and reporting of treatment errors in the British intensive care unit”. The project was conducted between January to April 2020.
 Results. Detailed analysis showed that the most important factors influencing the occurrence of adverse events in the drug administration are: nurses shortage (14%), stress and burnout syndrome (11%), incorrect labelling (13%). 85% of medical personnel are convinced that it is essential to monitor the situation of adverse events in drug administration. The Kruskal–Wallis test did not confirm the existence of a relationship between the: occurrence of adverse events in the area of pharmacotherapy and age (K – W = 0; p = 1), level of education (K – W = 3.6328; p = 0.3039) and work experience of the surveyed respondents (K – W = 0.3651484; p = 0.5457). Similarly, no significant relationships were found between the occurrence of adverse events and the department profile (K – W = 0.330; p = 0.5652).
 Conclusions. The level of education, professional experience and age are not significantly related to making mistakes in the area of drug administration; the factors that significantly affect the occurrence of AD in the area of drug administration are: reduced nursing staff on duty, performing one’s duties under stress and time pressure, insufficient variety of labels on medicinal products; the best method of prevention in the area of drug management and administration is the presence of a reporting and monitoring system; the was the majority of nurses reported the occurrence of a drug-related adverse event to the rest of the therapeutic team. (JNNN 2022;11(2):65–73).