This monograph examines the impact of direct and indirect government intervention in Colombia's coffee, cotton, rice, and wheat markets between 1960 and 1983 and compares it with the situation that would have prevailed in the absence of intervention. The effects of intervention on prices, production, consumption, net foreign exchange earnings, the real income of producers and consumers, and transfers of income between agriculture and the rest of the economy are evaluated. As a result of state interventions (direct and indirect) in the market for the four commodities, production of these commodities fell below its potential level : a difference of 20 % for coffee and rice, 40 % for cotton, and 15 for wheat. These interventions were maintained even though they hurt agricultural producers. The report points out that one reason for intervention is to help consumers, but the results show that real annual incomes of the poorest consumers of rice and wheat derived products never increased by more than 3 percent. Direct intervention, however, isolated the domestic from the international market and thus prevented the transmission of variations in international prices to domestic prices.