The purpose of this study was to investigate the aspects of primary school student teachers' writing ability. 580 first-to-third primary school student teachers were participated in the study and writing evaluation criteria was composed appropriateness and credibility of information on subjects to explain, systematic structure, appropriateness of expression and consideration of readers was used for the data analysis. Results from the study documented a very low level in primary school student teachers' writing ability. Regarding gender effect on their writing ability, results indicated that female as a group possess more positive writing ability than male at all grade levels. And regarding major field effect on their writing ability, results indicated that students major in humanities & social science field and arts & physical field possess more positive writing ability than students major in natural science field at all grade levels. To solve such problems, it is necessary to make efforts for improving writing courses at teachers' college. Also, it is required establish permanent feedback and assessment system of students’ writing.