The crystallinity of hydroxyapatite (HA) coatings used in femoral implant applications is a crucial factor. A coating containing a large percentage of amorphous phases will dissolve quickly. This leaves the coating mechanical weak and thus reduces its functional life. The crystallinity of the final coating largely depends on the parameters selected during the spraying process. In this study the design of experiment technique was used to investigate the parameters that have the greatest effect on the crystallinity of the coating. The effect of furnace heat treatment in air at 600°C, 700°C and 800°C on the crystallinity of the coating was also investigated. The coatings were analysed using scanning electron microscopy (SEM) and X-ray diffraction (XRD).