There is a clear need that every individual in a society should be well informed about the organ donation and transplantation issue to contribute to the efforts to increase low donation rates. Science teachers have a crucial role in increasing young pupils' knowledge and awareness of organ donation by providing them with the necessary scientific information. Therefore, the present research examined the knowledge, practices and behaviors of pre-service science teachers regarding organ donation and transplantation, to help them to be better prepared science teachers. A total of 265 participants from two universities in Turkey responded to an organ donation and transplantation questionnaire. Descriptive statistics, t-test and chi-square test were used in the data analyses. While 92.8% of participants supported organ donation regardless of their year of study, only 1.1% declared that they were registered to be a donor. Pre-service science teachers in this study showed generally a low level of knowledge regardless of their year of study and gender. Despite having a low level of knowledge regarding organ donation and transplantation, they were generally willing to donate their own organs. These findings raised questions about the extent to which pre-service science teachers have the necessary knowledge, practices and behaviors to support student learning when they become real teachers. The implications of these findings for science teacher education in Turkey was also addressed.