This research is focused on dimensions of mathematical thinking among preservice teachers learning through the use of e-Portfolios. The data came from portfolios created and reconstructed by future mathematics teachers. Their process of reviewing and republishing pages through the Internet was constantly saved and reviewed in turn by the researchers. Seven case studies were conducted. Results stress the importance of the use of ICT by pre-service teachers as an interface to become more reflective about their learning and to improve their knowledge. Besides being a tool to recognize different dimensions (technological, conceptual and communicative) the e-Portfolios were a powerful resource for creating, publicizing ideas, and learning mathematics in different ways. The article also presents some methodological issues. (Contains 4 figures, 3 tables, 4 footnotes, and 1 picture.)