The precipitation of ammonium perchlorate (AP) from methanol solutions of AP by a salting out method has been studied. The organic solvents studied as precipitants were : chloroform, ether, isobutyl alcohol and methylene chloride. The characteristics of the precipitated AP crystals were investigated by means of scanning electron micrograph X - ray diffraction, differential scanning calorimetry and thermogravimetric analysis. When ether, chloroform and methylene chloride were the precipitants, the product crystals had a particle size less than 5 mu m. On the other hand, the crystals obtained with isobutyl alcohol as the precipitant had a orthorhombic shape and the mean crystal size was larger than 10 mu m. Diffraction angles for AP crystals obtained a with isobutyl alcohol as the precipitant coincided with those obtained with other precipitants used in this work, though the intensity in the X - ray diffraction changed.