<p>Although several studies investigate the ideas of students and teachers about Nature of Science (NOS) in elementary and secondary education, research on NOS understanding of young children and early years teachers (in- and pre-service) is rather limited. However, an insufficient NOS understanding of the latter may affect their instructional choices and their students’ NOS understanding. Moreover, including NOS in early years education may contribute to forming the basis for comprehending scientific concepts, acquiring scientific skills, and shaping positive attitudes towards science. Considering the above, we investigated the understanding of pre-service early years teachers about specific aspects of NOS. We administered a questionnaire with closed-ended and open-ended items to 97 pre-service early years teachers in order to trace their understanding of specific NOS aspects such as the role of creativity and imagination in science, the provisional nature of scientific knowledge, the integration of science within socio-cultural contexts, and the distinction between observation and inference in science. According to our findings, the participants expressed a rather insufficient understanding of NOS, giving few informed answers. Concerning different aspects, the aspect of creativity in science was found to be the most challenging for them. On the contrary, the aspect of the provisional nature of scientific knowledge was found to be the most comprehensible. Relevant implications for research, policy and practice are discussed.</p>