This study was conducted to investigate EFL cooperating teachers' roles and practices in mentoring as perceived by cooperating teachers and student teachers in the regions of Muscat, Batinah South and Dakhiliya. The study aimed at finding out the differences between the cooperating teachers' and the student teachers' perceptions of the importance of the roles the cooperating teachers play and responsibilities they perform in helping student teachers during teaching practice and how much these roles are actually practiced. Furthermore, the study compares cooperating teachers' and student teachers' perceptions with respect to regions. It also aimed at identifying the obstacles that both cooperating teachers and student teachers face in teaching practice. A total of (387) EFL cooperating teachers and student teachers participated in this study by completing a questionnaire. They completed a 57 item questionnaire covering the most essential responsibilities cooperating teacher might take part in to help student teachers' professional development. These items were organized into four categories representing different areas of teaching. In addition, other (30) cooperating teachers and student teachers were interviewed to find out the problems both groups faced in teaching practice. The results obtained through the questionnaire showed that most EFL cooperating teachers and student teachers in teaching practice schools found most of the cooperating teachers' responsibilities contained in the questionnaire important for student teachers' development. On the other hand, results revealed that the actual practice of these cooperating teachers' responsibilities is less than desired. While examining the differences between the two groups, the results revealed that there were significant differences only in two categories of the importance of these responsibilities. Significant differences in the perceptions of cooperating teachers and the student teachers of the actual practice were found in all of the four categories in favour of the cooperating teachers. Furthermore, the study found no significant differences between the regions in all categories of the importance of cooperating teachers' responsibilities. Whereas, discrepancy between cooperating teachers' and student teachers' perceptions of the actual practice of the cooperating teachers roles and responsibilities with respect to regions were found only in one category in favour of Batinah South region. Comparing the perception of the importance dimension and the actual practice dimension, the results revealed that there were significant differences between perceptions of both of the importance dimension and the actual practice dimension in favour of the importance dimension.. Two separate lists of problems faced by cooperating teachers and student teachers were compiled from the interviews and these problems were arranged into six categories. Taking these findings into consideration, implications and recommendations were suggested.