The conservation of wide-ranging, territorial carnivores presents many challenges, not least the inadequacy of many protected areas in providing sufficient space to allow such species to maintain viable populations. As a result populations occurring outside protected areas may be of considerable importance for the conservation of some species, although the significance of these areas is poorly understood. Brown hyaenas Parahyaena brunnea are categorized as Near Threatened on the IUCN Red List and recent research suggests the species may be particularly vulnerable to habitat loss and the conversion of land to agriculture. Here we report on the population density and abundance of brown hyaenas in an area of commercial farmland in western Botswana. Mean brown hyaena density estimated from camera-trap surveys was 2.3 per 100 km2 and from spoor surveys 2.88 per 100 km2, which are comparable to estimates reported for protected areas. Estimated densities were higher on farms used for livestock production than on those used for game farming, suggesting that the species can tolerate land-use change where reliable alternative food resources exist. Our results indicate that populations of brown hyaenas in non-protected areas comprise a significant proportion of the global population and that such areas may be of critical importance for their conservation.