This study investigated prospective mathematics teachers' reflections on the experience of designing and conducting one-to-one clinical interviews with middle school students in the context of an elective course on use of video in teacher learning. Prospective teachers were asked to write about weaknesses and strengths in student understanding as well as their own performance as an interviewer in terms of asking questions and responding to student thinking in their reflections on conducting clinical interviews. Furthermore, prospective teachers were also asked to reflect on what they would do differently in order to conduct better clinical interviews. Nature of prospective teachers' reflections were analyzed by using existing frameworks (through constructs of reflection-on-action and reflection-for-action) and by using thematic analysis. Results of data analyses revealed that prospective teachers had more difficulties in providing meaningful reflection-for-action which was related to alternative decisions and planning for future similar interviews. Thematic analysis results revealed prospective teachers' learning were grouped under three categories: conducting clinical interviews as part of being a teacher, complexity of conducting clinical interviews, and personal theories about middle school students. There are implications for both teacher learning and research.