The structural modifications and the changes in crystallinity of poly(phenylenesulfide) (PPS) during high-pressure molding and curing have been investigated as a function of pressure and temperature using wide-angle X-ray scattering (WAXS), infrared absorption (IR) and scanning electron microscopy (SEM). It has been found that the crystalline content of the molds varies with applied pressure as P^α where α is 1.5. Major changes in the IR spectra are found in the range of 800 to 600 cm⁻¹ and attributed to structural modifications which have also been noted in the scanning electron micrographs. These various results have been mainly explained on the basis of plastic deformation and flow during the high-pressure molding process.