This work reviews the results of research conducted in the last five years on urban soils of the Campania region, southern Italy. Approximately 2000 topsoil samples were collected and analysed for 40 elements, among which are included the potentially harmful elements (PHE). The two most relevant objectives achieved were the determination of background levels for each element, using concentration–area (C–A) and separation–anomaly (S-A) algorithms, and the production of an extensive cartography, published in a series of geochemical atlases. The latter show that high PHE concentrations, exceeding many times the local natural backgrounds (especially Pb, Hg, Sb, Zn), are found in the most densely populated areas, often affected by heavy vehicular traffic and industrial activities. Many soil samples exceed the limits set for PHE by the Italian Ministry of the Environment in law DM 471/99 for residential land use. The geochemical maps can prove to be very useful both for scientists and professionals working towards the restoration of contaminated areas, as well as serving to refine the Italian environmental legislation to be more effective in local situations.