SIU is a consortium of Argentine universities that provides technology services for the National University System. One of its main products is the SIU-Guaraní system which is used by top universities all throughout the country with the purpose of managing students’ information. Within the context of a user-centered design methodology, we redesigned the information architecture and the interaction of the system. The project had two different sets of iterations with users in which we used usability tests at the beginning and iterative prototyping at the end. Results were very good with increases of 18% in effectiveness, 56% in efficiency and 26% in user satisfaction.