Annual land-use decisions of settlement farmers, estimated to approach half a million in the Amazon, can have significant impacts on forest conversion of the largest tropical moist forests. Given the biodiversity and climate change consequences of the disappearance of this forest, it is pivotal to understand these farmers reactions to combinations of technologies, policies, and institutional arrangements to predict their deforestation implications. This study aims to find whether settlement farmers in the western Brazilian Amazon will adopt more intensive production systems, and if they do, what the impact of this adoption would be on deforestation and farm incomes. Adoption of four types of intensification and their economic and environmental impacts were predicted using a farm level bioeconomic linear programming model. The four intensification types were: no intensification, intensification of non-livestock activities on cleared land, intensification on all cleared land, and intensification on both cleared and forested land. Intensified land uses on either the cleared or forested lands generate higher returns to labor and land, and thus will likely be adopted by settlement farmers. Also, intensification of non-livestock activities on cleared land resulted in the largest deforestation rates. Despite its lower deforestation rate, intensification on all cleared land (including pasture) resulted in the least amount of preserved forest after 25 years. More precisely it decimated the forest. Intensification on forested land low-impact forest management slowed the deforestation rate, but did not stop it unless timber prices were increased to R$550m-3 (a R$435 increase over 1994 prices). Even with intensified activities on forested land, pasture still dominated the landscape. In the long run, there is a trade-off between farm income and forest preserved, which results from intensification of land uses on the cleared land. Under the current socioeconomic and political setting existing intensification systems on the cleared land will not save the forest. Intensification systems on forested lands provide better hope because they increase the value of the standing forest, thus counteracting the pressure to deforest. © 2000 Elsevier Science B.V. All rights reserved.