Protected areas are increasingly used as a tool to fight against deforestation. This paper presents new evidence on the spillover effects that occur in the decision to deforest and the creation of protected areas in local administrative entities in Brazilian Legal Amazon over the 2001-2011 period. We also highlight the interdependence between these two decisions. We proceed in two steps. First, we assumed that protected areas are created to stop the negative effects of deforestation on biodiversity. In order to control for the non-random location of protected areas, biodiversity indicators are used as excluded instruments. This model is estimated using a spatial model with instrumental variables. Second, a simultaneous system of spatially interrelated cross sectional equations is used to take into account the interdependence between the decision to deforest and the creation of protected areas. Our results show (i) that deforestation activities of neighboring municipalities are complements and that (ii) there is evidence of leakage in the sense that protected areas may shift deforestation to neighboring municipalities. The net effect of protected areas on deforestation remains however negative; it is moreover stable across two sub-periods. Our results confirm the important role of protected areas to curb deforestation and thereby biodiversity erosion. Moreover, they show that strategic interactions deserve attention in the effectiveness of conservation policies.