Abstract A multireference Møller—Plesset method is derived. The state-specific nondynamical correlation is accounted for by the MCSCF theory and the transferable dynamical correlation is estimated by the Møller—Plesset perturbation theory. There is a very close parallel between the standard single reference Møller—Plesset theory and the present multireference version. The method has been implemented at the second-order for 2-configuration MCSCF wavefunctions in which only two electrons are correlated. Potential curves for H 2, HF and F 2 molecules agree well with the full or near-full CI results.