Abstract Calcium hydroxyapatite (HAP) was prepared by homogeneous precipitation using formamide and acetamide. The particles formed under various conditions were characterized by XRD, FT-IR, TEM, SEM, ICP, TG-DTA and N 2 adsorption. The crystallinity and morphology of the products depended on the kind and concentration of amides and the ageing time. The large rod-like well crystallized HAP particles were obtained in the presence of acetamide. Acetamide hydrolysed more slowly than formamide, forming a smaller quantity of nuclei resulting in larger HAP particles. However, the excess acetamide interfered with the formation of HAP.