This case study aims to explore the professional development experiences of two fourth-year student teachers (mentees, hereafter) and their two cooperative school teachers (mentors, hereafter) in the practicum component of English language teacher education program in a state university. The participants of this study were doing their internship in their last year of pre-service education. In order to understand the mentorship process in terms of professional development practice for those involved, two mentees and their mentors were interviewed. The results indicated that the relationship between mentor and mentee is continuous, dynamic, and fruitful for both parties. Mentees reported that they developed a teacher identity and improved themselves particularly in classroom management. Mentors also stated that they felt refreshed and had the chance to update their knowledge with the help of mentees. Implications for the mentorship and practicum process are discussed based on the results of this study.