Hydroxyapatite (HAP) is a biocompatible ceramic that is widely used in a number of biomedical applications and devices. Due the close similarity between nanometer scale forms of HAP and the mineral phase found in the natural bone matrix, recent studies have focused on understanding the structure of HAP for its inclusion in a new generation of novel composites. In this study two commercially available software packages Materials Studio and Endeavour® 1.7b were used to model the crystal structure of a nanometre scale HAP powder from X-ray powder diffraction data.