[en] Lepton pair production from polarized hadrons is studied in low order QCD perturbation theory. Like in the spin averaged case leading logarithm mass singularities are found to factorize and have the same structure as in deep inelastic lepton scattering. This justifies (up to terms 1/logQ²) the usual parton model approach: Hard scattering cross-sections are calculated as convolution of Q²-dependent hadron spin structure functions and Born term parton helicity cross-sections. The prescription also remains correct if polarization of final state leptons is measured. (author)