The aim of this study was to investigate what the prospective elementary mathematics teachers noticed and how their noticing changed in an environment in which they discuss on video cases. To achieve this aim, we asked senior elementary mathematics prospective teachers to watch and discuss videos depicting real elementary mathematics classrooms. In this qualitative study, the main data sources were the participants' reflection papers and interviews with the focus participants. The online discussions among the focus participants were also analyzed. For the analysis, the Learning to Notice framework (van Es & Sherin, 2002) was used. The findings suggested that prospective teachers noticed several issues related to teacher actions that reflect specific domains of teacher knowledge, and their noticing increased over time. In conclusion, it is suggested that the use of case-based pedagogy in teacher education is an effective way to help future teachers get ready for the profession.