Introduction: The most common reason for the adverse events in healthcare is communication. Due to the development of health technologies and the increasing specialization of care, more and more healthcare professionals are involved in the treatment of patients, resulting in an increasingly important role and risk for patient handover. Aim: To present the current state of knowledge of patient handover through the results of an international project. Method: Self-developed, anonymous questionnaires with single and multiple choice questions were used to investigate handover knowledge among healthcare workers in 3 Hungarian and 3 Polish hospitals. The frequency of responses was analyzed according to their correctness. The factors that can influence the knowledge were studied using a regression model in the Hungarian sample. Results: The questionnaire was completed by 63% of the 2963 employees who received the questionnaires. In the two countries, there was no significant difference in the proportion of correct responses. Nearly half of the responders (49.4%–45.7%) gave the right answers to the question about the definition of patient handover. The lowest rate of correct answers (14.4%–11.1%) was given to elements of patient handover techniques. The difficulty of the questions also showed a similar pattern. Conclusion: Based on the results, it can be concluded that knowledge of handover needs to be improved in both countries. Although healthcare providers have some knowledge about handover, it cannot be considered accurate and complete. It is important to promote the knowledge and practice of handover together for the safety of patients and healthcare providers. Orv Hetil. 2019; 160(44): 1735–1743.