Thin films of ZnS were prepared by spray pyrolysis. The effect of substrate temperature as well as deposition time and annealing in air and in a nitrogen atmosphere on some structural features was investigated by X-ray diffraction. At a substrate temperature of 300 degrees C, ZnS appears almost in amorphous form. With rising substrate temperature, the crystallinity was improved. At 550 degrees C, a well-crystallized cubic phase of ZnS was obtained. The films were preferably oriented with the [111] direction perpendicular to the surface. Annealing in air created ZnO, no evidence for oxides was found when annealing was carried out in a nitrogen atmosphere. Therefore, using a spray pyrolysis technique with a substrate temperature of 500 degrees C and annealing in a non-oxidizing atmosphere for about 120 min, one can obtain well-crystallized single-phase cubic ZnS thin films.