This paper presents a novel approach to the preliminary, low-cost, national-scale mapping of wind energy, solar energy and certain categories of bio-energy resources in developing countries, using Mali as an example. The methods applied make extensive use of satellite remote sensing and meteorological mesoscale modeling. The paper presents first results from applying the methodology in Mali and discusses the appropriateness of the results obtained. It is shown that northern Mali has considerable wind energy potential, while average wind speeds in the southern part are too low to make wind power a competitive option. Solar energy resources are shown to be abundant in all of Mali, though the highest values are found in the south. The temporal variation is relatively limited. Bio-energy resources are also concentrated in the south, but there are small pockets of high vegetation productivity in the irrigated areas of the Niger inland delta that might be interesting from a renewable energy resource perspective. Finally, the paper discusses the role that renewable energy resources might play in the energy systems of Mali, given the spatio-temporal distribution of renewable energy resources. It is argued that at the current price of about 70 US$/barrel for fossil fuels, renewable energy resources are becoming economically as well as environmentally attractive options.