We study early stages of spinodal decomposition (SD) in polymer/liquid crystal mixtures by solving linearized time-dependent Landau-Ginzburg equations for concentration (conserved order parameter) and orientation (nonconserved order parameter). We find a new SD process driven by instability of the orientational order parameter. In this case, the scattering peak of compositional structure factor evolves continuously to lower wavenumber via a series of power law regimes, which is initiallyt1/3in our minimal model. ©2000 American Institute of Physics.