This papers examines the terms of trade and Granger causality between prices received and paid by the Brazilian agricultural sector, from 1986 to 2004. During that period, the terms of trade improved for the agricultural sector. The greatest improvement occurred before 1994; in 1995 the terms of trade fell, followed by a relative stabilization until 2004. The valorization in the whole period was due to agricultural products, since animals products had a significant decline in their terms of trade. Products with the greatest losses were coffee, wheat, potatoes, chicken and hogs. Regionally, the greatest losses, after 1994, occurred in the Northeast States, with the exception of Maranhão and Bahia. The Granger causality shows that agricultural prices did not cause the prices paid, considered as a whole, between 1986/2004; but they caused the prices paid for specific inputs, like fuel oil, seeds and services before 1994, and the prices of pesticides, seeds and services after that year. The effect of the prices paid on the prices received was greater in the first period than in the second one. With the opening of the economy, the prices received became more influenced by external factors than by inputs prices.