A novel VIMOX (volume identical metal oxidation) route to near-net-shaped calcium hydroxyapatite, Ca-10(PO4)(6)(OH)(2), is demonstrated: the oxidation of machinable Ca-Ca2P2O7 precursors. Mechanically alloyed mixtures of Ca and beta-Ca2P2O7 were compacted into disk- and bar-shaped preforms. The latter preforms could be machined into cylinders using a metalworking lathe (200 rpm, hardened steel tooling). After oxidation at 600 degrees C in O-2, and then postoxidation annealing in H2O/O-2 mixtures at 850 degrees C and 1150 degrees C, phase-pure hydroxyapatite was obtained. Because of offsetting volume changes from calcium oxidation and hydroxyapatite formation, porous hydroxyapatite bodies were produced that retained the shapes and dimensions (within 1%) of the machined precursors.