The aim of this study is to investigate the situation of pre-service science teachers' pedagogical content knowledge (PCK) about the nature of science (NOS). Study is being carried out by using " Holistic Multiple Case Design" of qualitative research methodology. Population of research is chosen from 89 pre-service science teachers by the maximum variety sampling method that was executed with 5 pre-service teachers. Pre-service teachers' PCK about NOS was identified with "Views about the Nature of Science (VANS) Questionnaire", " VNOSC Questionnaire" and also the triangulation method. HyperRESEARCHTM 2.8.3. Analysis Program was used in the content analysis. As a result of analysis, it is found that the pre-service teachers' knowledge of nature of observations, hypotheses, theories and laws in the naive level; the knowledge of definition of the scientific, the knowledge of characteristics of the scientists, the information of the nature of the classification scheme in the realistic level. But it has been identified that there is no relationship between the pre-service teachers' subject matter knowledge about NOS and components of PCK about NOS. Also, in general the interviews about pedagogical knowledge and the classroom practices of the pre-service teachers differ from each other. Furthermore, it is determined that inadequency about teaching the NOS caused especially by the weakness of their self-efficacy beliefs.