The purpose of this study was to investigate the advantages and disadvantages of using GeoGebra in an argumentative application. For this purpose, the data were collected from eight prospective elementary mathematics teachers via video recordings, reflection papers and interviews. Data were analyzed through qualitative data analysis methods. According to the results, making accurate drawings, creating confident justifications based on exact measurements, dragging objects to see relationships and saving time were the main advantages of GeoGebra in argumentation. On the other hand, not attending class discussion and not reasoning the relationships after measuring with GeoGebra were the disadvantages for argumentation.