This paper attempts to estimate the effects of some of the changes in the marketing system on the Western Cape Province of South Africa, utilizing a regional linear programming model of the agricultural sector of the region. The model includes supply, demand and production risk, and simulates the present agricultural production structure well. Market and trade liberalisation have major impacts on the structure of Western Cape agriculture, particularly the grain and livestock sub-sectors, with only marginal and mostly insignificant effects on horticultural products.