Based on detailed observations of how senior officials and forest rangers collaborate together using geographic information systems (GIS) this article examines the contradictory role of boundary objects in the enforcement of deforestation control policies in the Brazilian Amazon rainforest. Specifically, we unpack the mechanisms behind the way in which these artifacts have simultaneously facilitated joint work and fostered conflict between different groups working in the region. From these observations it emerged that the reification of work related the role of GIS as a boundary object contributed on the one hand the emergence of new forms of collaboration at a distance but on the other hand led to a process we call boundary-blinding, namely, the inability of managers to understand the practices and outcomes of the work of the groups across boundaries. From that the paper proposes a (re)conceptualization of the notion of boundary objects that pays particular attention to the process of reification and its contradictory outcomes in the context of joint work. The paper also concludes point out to some of the challenges involved in fostering inter-departmental collaboration through ICT in the public sector.