This is a preliminary study that examines prospective teachers' reflective thinking as it is exhibited in their action research during the teaching practice experience. Different systems of analyzing reflective thinking are reviewed and criticized for their suitability for analyzing written journals rather than other forms of expressing and developing reflection. An inventory for analyzing student teachers' reflective thinking during action research is constructed and validated (IRTAR). It is then used for analyzing action research reports of hundred prospective teachers. The results of the analysis are discussed within the context of teacher education programs in Egypt.