The current understanding of the atomic and electronic structure of polar cubic 3C-SiC(001) surfaces, as it derives from ab-initio calculations, is briefly addressed in the light of recent experimental data. Very encouraging agreement between the theoretical results and the available data is observed. The origin and nature of the distinctively different reconstructions of 3C-SiC(001) surfaces, as compared to those of the C(001) and Si(001) surfaces, is discussed.