The purpose of this study was to examine elementary preservice teachers' mathematical knowledge for teaching. Twenty-seven third year preservice teachers enrolled in classroom teaching program participated in this study. Data were collected through written documents (preservice teachers' response to open-ended questions about addition and subtraction operations) and semi-structured interviews. In this study, 'Mathematical Knowledge for Teaching' framework developed by Ball, Thames and Phelps (2008) was used for the analyses of the data. Results revealed that most of the preservice teachers' content knowledge was developed. However, a few had limited 'Specialized Content Knowledge'. For Pedagogical Content Knowledge, most of the preservice teachers had tendency to choose short and practical approaches that were used by their elementary teachers.