The polarization dependence of the (2 + 1) and (3 + 1) resonance enhanced multiphoton ionization of OCS have been investigated in the 70 500-74 500 cm(-1) energy region. This region contains a complex system of bands arising from the excitation of the 4p Rydberg states. The symmetry of most of the observed bands have been unambiguously determined based on the intensity changes of the two and three photon resonant spectra using both linearly and circularly polarized light. These results generally confirm the assignments suggested in a previous study. New bands have also been observed and some new assignments are proposed. The vibrational frequencies v(1), v(2), and v(3) of the Rydberg states in that energy region are determined.