The "Solar and Wind Energy Resource Assessment" (SWERA) project was an international project financed by GEF/UNEP, which aimed at providing a consistent and accessible database to foster the insertion of renewable energies on the energy matrix of developing countries. This paper presents the solar energy resource assessment generated during the SWERA project by using the radiative transfer model BRASIL-SR fed with satellite and climate data. The solar irradiation estimates were validated by comparing with the ground data acquired in several sites spread out the Brazilian territory. Maps on 10 x 10 km(2) spatial resolution were generated for global, diffuse and direct normal solar irradiation. Solar irradiation on a plane tilted by an angle equal to the local latitude was also generated at the same spatial resolution. Besides the solar resource maps, the annual and seasonal variability of solar energy resource was evaluated and discussed. By analyzing the Brazilian solar resource and variability maps, the great potential available for solar energy applications in Brazil is apparent, even in the semi-temperate climate in the southern region where the annual mean of solar irradiation is comparable to that estimated for the equatorial Amazonian region. (C) 2008 Elsevier Ltd. All rights reserved.