The poly(p-phenylene terephthalamide) (PPTA) spherulite grown from a concentrated sulfuric acid solution and its hydrolysis products were investigated by electron microscopy and X-ray diffraction. Sharp Bragg reflections and their spacings indicated that the nascent spherulite consists of complex crystals of PPTA and sulfuric acid. All the diffraction spots from the hydrolysis products of PPTA/H2SO4 spherulites could be associated with the Form II crystal with one exception on the equator. This exceptional spot had a fairy strong intensity in the diffraction patterns from air-dried spherulites and was assigned to the (100) reflection. On the other hand, the intensity of this reflection could not be expected from the packing arrangement of the Form II crystal. To explain the intensity of (100), the Form II crystal structure was modified and water was introduced into the unit cell. The structure found showed good agreement between observed and calculated structure amplitudes. Further, the calculated amount of bound water was almost the same as that lost by annealing above 400 K.