Introduction: Transplantation and organ donation are important medical procedures that represent the pinnacle of modern medicine, organ donation is an act by which an individual gives one or more of his organs, often after death, but also during his lifetime to help others in need. Education and raising public awareness of the importance of organ donation are key to increasing the number of donors and saving more lives, the knowledge and attitudes of future health professionals about transplantation and organ donation are particularly important, because they can contribute to raising public awareness of this topic through their active activities. which can influence the increase in the number of donors and transplanted persons in the population. Objective: To examine the knowledge and attitudes of undergraduate and graduate nursing and medical students at the Catholic University of Croatia about transplantatio and organ donation. Methods: A total of 188 undergraduate and graduate nursing and medical students of the Catholic University of Croatia participated in the research. The knowledge and attitudes of students about organ donation were examined with an online survey that was used with the consent of the author, assistant professor of science, Nenad Karanović, MD. Results: Examining the knowledge and attitudes of medical and nursing students of the Croatian Catholic University about organ donation found no significant difference in knowledge about organ donation between medical and nursing students. Female students have statistically significantly more positive attitudes towards organ donation compared to male students (t= 4.25, p=0.000). Medical and nursing students have positive attitudes towards organ donation, but a significant statistical difference was observed related to the religious- ethical aspect of their attitudes, in which nursing students have a more favorable attitude towards organ donation compared to medical students (t= 4.19, p= 0.003). Students who declare themselves as believers have a less favorable attitude towards religious statements than agnostics/atheists who fully agree with the same statements (t= 4.50, p= 0.004). Conclusion: Students are aware of the basic terms and procedures related to organ donation. Attitudes towards organ donation are mostly positive, recognizing the importance and significance in saving lives. The majority of respondents see donating organs as an act of altruism and love for others, but there is still a need for additional education. Education should include medical, legal and ethical aspects and promote a positive attitude towards donation. Although the students of the Croatian Catholic University generally have a positive attitude towards organ donation, there is room for improvement of knowledge and better information in order to ensure greater willingness to donate and understanding of all relative aspects.