In the frame work of a tight-binding model, we have theoretically investigated the interfacial spin polarization of organic polymers in a heterostructure of ferromagnetic metal/conjugated polymers. Dependence of the spin polarization on the strength of the electron-pbonon coupling in a polymer and the spin-dependent interfacial coupling were discussed. It was found that the spin polarization within an organic chain is weaker than that within a metal chain, but stronger than that within a semiconductor. (c) 2004 Elsevier B.V. All rights reserved.