A. Rorsch TNO Board of Management In 1985 the Netherlands Organization for Applied Scientific Research TNO, in cooperation with the Netherlands Ministry for Housing, Physical Planning and the Environment, took the initiative for a conference on an important environmental problem: contaminated soil and groundwater. We named it, somewhat self-assured, the First International TNO Conference on Contaminated Soil. And indeed the contamination of soils and groundwater proved to be an environmental issue of such an extent that soon after the successful first conference, TNO started preparations for a second one, this time in cooperation with the State Ministry for the Environment (Umweltbehorde) of Hamburg. And now we are on the brink of the third conference, organized together with the Karlsruhe Nuclear Research Centre (Kernforschungszentrum Karlsruhe). We feel honoured that the Federal Ministry for Research and Technology (BMFT) is again generously supporting this conference, and has anew declared it a BMFT Status Seminar. The conference (generally referred to as Contaminated Soil ‘85, Contaminated Soil '88 and Contaminated Soil '90, respectively) has successively gained in importance and prestige, which is reflected by the increasing number of participants and contributions to the scientific programme.