This study aims to analyse prospective chemistry teachers' cognitive structures related to the subject of oxidation and reduction through a flow map method. Purposeful sampling method was employed in this study, and 8 prospective chemistry teachers from a group of students who had taken general chemistry and analytical chemistry courses were included in the study. To determine participants' cognitive structures related to the subject of oxidation and reduction, participants were asked two questions which did not guide them. Then the answers they gave to the questions were collected, and a flow map for each participant was prepared. The flow maps obtained through participants' written narratives were analysed in terms of quantitative variables used in presenting cognitive structures in quantitative statements. On examining participants' flow maps in accordance with all the quantitative variables used in presenting cognitive structures, it was found that prospective chemistry teacher 8 had the largest comprehensive cognitive structure, prospective chemistry teacher 4 had the medium comprehensive cognitive structure whereas prospective chemistry teacher 1 had the narrowest comprehensive cognitive structure. Participants' misconceptions were also determined through flow maps.