Soil sealing (permanent covering of an area by impermeable artificial material) is one of the most serious problems affecting ecosystems in Western Europe. Numerous studies have analysed this issue from an ecological approach, but very few take into account its impact on one of soil’s essential functions, namely the preservation of archaeological sites. Spanish laws on historic heritage (1985) and environmental impact (2013) have tackled the matter by legislating measures for the preservation of heritage. Furthermore, in 1992 Spain signed the Valletta Treaty (the European Convention on the Protection of the Archaeological Heritage) of the Council of Europe, and further ratified it in 2011. Historians, archaeologists and soil scientists should respond to this threat using a multidisciplinary approach. The present study analyses the impact that soil sealing has had on the Roman city of Complutum, located on the Henares River plain (Madrid, España) on highly fertile Fluvisols and Calcisols. One of the aims of this study is to show that the combined use of aerial photos and satellite images provides a continuously updated file of urban development processes and therefore makes it possible to foresee the impact on archaeological sites. At present, medium and high spatial resolution images (Spot and Landsat satellites) can be obtained free of charge and digital processing makes it possible to map any variations in these sites. Another aim of the study is to analyse the importance of soil type and quality in establishing settlements in corridors which have served as important communication routes. There is a greater likelihood of urban planning and development processes in the immediate surroundings of these routes over the years, implying that it is highly probable that pre-existing sites will be destroyed.</p><div> </div>