On two Brazilian sites (Acre and Rondonia), and on two Peruvian sites (Yurimaguas and Pucallpa), deforestation rates and patterns are verydifferent. To illustrate these differences, two major factors contributingto deforestation are selected : how accessible the frontier is for people including access to markets; and land abundance and land rights and markets. Even if there are commonalties between Brazil and Peru, major differences are identified. Road access to the frontier is much greater in Brazil, linking the forest to the rest of the country; most of the Brazilian farmers have gained legal title through colonization projects or by claiming land after clearing. However, access to good land in Brazil is limited and landspeculation is high, whereas, in Peru there is plenty of room for expansionand land access is free.