The evaluation of the structural performance of Itaipu Dam involves, among other activities, the analysis of data from instruments installed at different points of the structures and their foundations. A widely used instrument is the piezometer, which allows monitoring of uplift pressures and pore water pressure occurring in the foundation of the structures and in the body of the earthfill and rockfill dams. The piezometers provide information regarding the pressures caused by water infiltration via discontinuities in the rock mass, as well as via the pores of the earthfill. The variable supplied by the piezometers is called piezometric head, which can be converted into pressure. Monitoring is carried out in several features over large areas, which in many cases include the whole foundation of Itaipu. The main features are the contacts between structure and foundation (concrete and rock or soil and earthfill) and discontinuity or porous zones (geological faults, basaltic breccias and fractured zones, in addition to strategic points in the embankment dams). In general, the analysis of these data is performed in a timely manner, using the time series obtained by the instruments, where current values are compared with historical highs and with theoretical values obtained via mathematical models that simulate critical load situations. However, spatial evaluation allows a greater understanding of the hydrogeological phenomena, since these do not occur locally, being instead results of features’ characteristics, of the drainage and waterproofing systems, and of treatments given to the foundation, as well as of the loads imposed by the presence of the reservoir and the rainfall patterns. Thus, this work aims to present the development of piezometric head and uplift pressure maps to modernize and improve the analysis of the performance of Itaipu's structures, based on mathematical interpolation and the use of Geographical Information Systems.