A novel ab initio method is presented for characterization of electron transfer (ET). The method utilizes perturbed ground state (PGS) properties of the ET systems in order to evaluate the electron donor-acceptor coupling and the donor-acceptor energy splitting. Since no excited states are involved in calculations, density functional implementation of the method provides an efficient way to include electron correlation effects for ET in large chemical systems. The PGS method is applied to two model systems and is compared with high-level ab initio results. The PGS method performs very well for the test systems. The method is more general than traditional techniques, providing both the ET coupling and the donor-acceptor energy splitting.