The aim of this study is to determine conceptions of preservice mathematics teachers’ (PMTs’) on quadrilaterals through concept map method. This qualitative study is conducted with 26 PMTs. As a data collection tool, documents are obtained through concept map technique which has low guidance, such as “design a map”. With this technique PMTs were asked to draw a concept map on quadrilaterals and each student made his/her own map. The PMTs’ drawings and highlighted concept definitions related to quadrilaterals in concept maps were analyzed descriptively whether they are correct or not. The findings showed that most of the PMTs used geometric figures in forming their own maps and they made generally partition classifications. Also the participants drew squares, parallelograms and rectangles most, and rhombuses and trapezoids least. Besides, the explanations of the wrong drawings showed that PMTs had the necessary knowledge of quadrilaterals, but they ignored this knowledge in their drawings. Finally, it was determined that the participants defined trapezoid as a ‘quadrilateral with only two parallel sides’.