Aqueous solutions of poly(vinyl alcohol) (PVA) were investigated by elastic and inelastic light scattering. In the initial stage of phase separation, a plot of the logarithm of scattered intensity against time formed a straight line when measurements were made in the sol region at less than the spinodal temperature estimated according to the method described by Cahn as being within the framework of linearized spinodal decomposition theory. No scattering pattern under Hv polarization conditions in the initial stage was observed for PVA gels prepared from aqueous solutions, apart from the X-type scattering pattern observed for PVA gels prepared from a dimethylsulfoxide/water mixture. This means that an aqueous solution of PVA does not form assemblies of crystallites such as rod-like and spherulitic textures in the phase-separation process. Hence the phase separation of aqueous solutions of PVA is apparently expected to be similar to that of amorphous polymer solutions due to spinodal decomposition. However, no definite scattering peak was observed as a function of scattering vector characterizing the latter stage of spinodal decomposition. Furthermore, in the initial stage, in the linear part of the plot of logarithm of scattered intensity against time, the decay rate estimated by inelastic light scattering decreased rapidly, indicating the progress of gelation. These contradictory phenomena indicated the possibility that the phase separation of aqueous PVA solutions is attributed to the simultaneous progress of spinodal decomposition and gelation.