Plasma spraying of hydroxyapatite (HA) coatings on human implants is considered to provide a promising means of enhancing their biocompatibility and improving tissue growth. This paper briefly describes a method of extracting HA powder from a biological source, namely human teeth. The physical and chemical characteristics of the derived powder are studied and the suitability of this powder for plasma spraying applications is ascertained. The deposited coatings are found to retain the chemistry characteristic of the apatite. Typical results of metallographic and scanning electron microscopy (SEM) studies and hardness measurements on the sprayed HA coatings are presented. © 1993 Chapman & Hall.