Arid and hot climatic conditions influence the development of surficial (superficial) sediments by aggravating the desiccation and weathering processes. Such environmental factors promote the occurrence of expansive soils in the Middle East. This study deals with the nature and extent of expansive soil problems in major development areas of Saudi Arabia where severe damage has been experienced in numerous projects. The expansive soils primarily consist of shales of Tertiary age which occur in a narrow strip adjacent to the western boundary of the Arabian Shield. Profile characteristics, geotechnical properties and swell behaviour of the shales are presented. Model equations were developed by nonlinear regression analysis for prediction of swell parameters from easily determined geotechnical indices.