Population estimation with questionnaires and demographic models is time consuming and usually accompanied by high costs. Geoinformation tools constitute key tools towards the solution of this problem, and, therefore, studies have started to emerge in the early 70s. In this paper a brief reference to the methods of population estimation, which are based totally or in combination with statistical analysis methods on products of Remote Sensing and their processing with GIS is cited. Afterwards, the capability of stereoscopic satellite images of high spatial resolution for the determining of the height of buildings and the performance of their plans, which are essential data for the estimation of the population of each building is highlighted. The study area is the municipality of Thessaloniki (Northern Greece, Region of Central Macedonia), and the estimation accuracy of the population reaches 97.06%.