GEOME is a web-based platform for the combined analysis of spatial environmental and molecular data. It implements tools for population genetics and spatial analysis. It has been developed to provide objective criteria for optimal biodiversity conservation measures. Although resource conservation managers increasingly have to use geo-environmental information and spatial analysis approaches, they do not have the tools and are not trained to do so. The web component of GEOME allows centralized service and technical support, encouraging the emergence of a community of users. GEOME therefore supplies a unique service of decision support based on free environmental data and open-source technologies.