Pedagogical content knowledge is consisted of two components: student knowledge and teaching strategies. Teaching strategies was defined under two sub-headings as strategies for specific topics and specific strategies for any topic. The purpose of this study was to examine the method with which quadrilaterals were taught by mathematics teachers with regard to the teaching strategies component of pedagogical content knowledge. 30 middle school mathematics teachers working at 12 different schools in Turkey participated in this study. Interview method was used for data acquisition. The interview was intended to put forth the strategies that the teachers used for defining, classification and visualization which were included in the strategies of the framework used for the study. Content analysis was used to analyze the data acquired in this study. Study results showed that the definition strategy was used together with the visualization strategy. It was also determined that informal definitions were used in addition to formal definitions and that in general a personal definition was given by listing the various properties of quadrilaterals. The teachers who participated in this study generally used the partial classification of quadrilaterals and the transformation classification of quadrilaterals.