"Modern conservationists portray national parks as part of a common world heritage and as essential components of sustainable development. The rules of new 'commons', however, often abrogate existing common property rights. After nearly three hundred years of continuous use, the Wameru people have been denied access to the forests and grasslands of Mt. Meru by the creation of conservation zones. This paper examines the nature of the continuing social conflicts which have resulted from the criminalization of local people's use of the commons. It pieces together the historical use of the area now enclosed by the park, investigates local people's interpretation of and response to the state-initiated regulations, and concludes with the implications for sustainability of the accepted model of national parks in Tanzania and elsewhere."