T he aim of the present research was to investigate the impact of utilizing the corpus approach on developing EFL writing skills among student teachers. The participants of the study consisted of third year English section students enrolled in Faculty of Education, Benha University (N=23). The study followed the one-group pre-post test design. In addition, it was a mixed-research study including both quantitative and qualitative methods for collecting and analyzing the data in order to enhance the credibility of the research findings. The instruments of the present study were divided into two parts: (1) instruments used for quantitative analysis including: an EFL writing test and a rubric to score it and (2) instruments used for qualitative analysis including: a Semi-Structured Interview (SSI), a Questionnaire of Corpus Use (QOCU) and an Evaluative Questionnaire (EQ). Furthermore, the researchers analyzed the essays and paragraphs written by the students as an assignment at the end of some sessions, in addition to self-reports written by the students about when and how they used the corpus in their writing. A Corpus-Based Program (CBP) was implemented to the participants during the second semester of the academic year 2014/2015. Results of both the quantitative and qualitative analysis revealed that the participants' EFL writing skills were developed significantly as a result of the CBP. Therefore, the corpus approach was recommended to be integrating into EFL writing instruction.