A study was undertaken to obtain more accurate structural information on poly(p-phenylene sulfide) (PPS) through Rietveld analysis. A few samples of PPS crystallized in a relatively wide range of physical conditions were selected with the aim of eventually identifying the occurrence of structural modifications induced by the various crystallization procedures. According to the results, the structural modifications are relatively small and essentially confined to variations of the C-S-C angle, for which values within the range 102 degrees-105 degrees were found close to those proposed by Garbarczyk. In particular, the strong influence of the amorphous phase in determining the crystallographic cell dimension was investigated.