Local sheep and goat breeds are generally argued to be remarkably well adapted to marginal rural areas. The latter are often said to be particularly or solely suitable for extensive husbandry mostly based on small ruminants. However, many local sheep and goat breeds are presently endangered. Both conserving these breeds and maintaining an active agricultural presence in marginal areas are presently two major priorities for agricultural and rural development policy in Europe. The objective of this paper is to analyse the spatial link between the geographic distribution of traditional, locally adapted sheep and goat breeds and the relative marginality of regions. The concept of marginal areas is discussed and defined and an index of relative marginality is computed in a Geographic Information System. The index combines land use, demographic and socio-economic data. The correlation between the marginality of a region measured by the index and the geographic distribution of sheep and goat breeds is analysed using a simple logit model. The broader interest of the index as a tool for agricultural and rural development policy applications is then discussed. (c) 2007 Elsevier Ltd. All rights reserved.