The crystallinity of poly(phenylene sulphide) (PPS) blended with polystyrene has been investigated as a function of composition, annealing time and temperature by an X-ray diffraction technique for samples made by three mixing techniques viz. powder blending, melt blending and solution blending. The method of blending has a pronounced effect on the crystallinity, solution blending giving the least for a particular composition. The crystallization half time increases while the crystallite size is reduced considerably by the addition of polystyrene to PPS. These findings have been explained on the basis of partial miscibility of the amorphous phases. © 1987.