Abstract Spin-dependent transport through single-wall carbon nanotubes (SWCNT) is studied theoretically within the single-band tight-binding model. The non-equilibrium Green's function technique is used in order to compute current–voltage characteristics and estimate the GMR effect. Electrodes are modeled as infinite slabs with FCC (1 1 1) surfaces perfectly matched at the interfaces to the finite SWCNT. It is shown that apart from size-effects, the strongest impact on the GMR comes from the electrode-surface magnetization and quality of the interfaces.