COBRAS/SAMBA is an ESA mission designed for extensive, accurate mapping of the anisotropies of the Cosmic Background Radiation, with angular sensitivity from sub-degree scales up to and overlapping with the COBE-DMR resolution. This will allow a fun identification of the primordial density perturbations which grew to form the large-scale structures observed in the present universe. Here we present the scientific goals and the key characteristics of the model payload and observation strategy.