Full field hard x-ray microscopy has recently been developed utilizing synchrotron light, enabling absorption and phase contrast imaging with a spatial resolution of 50 - 100 nm. This technique has allowed us to image bone tissue at the nanoscale level, viewing the substructure of mineralized collagen fibers. Thin sections of tissue (5 and 50 μm thick) from the L3 vertebrae of Beagles and mineralizing MC3T3-E1 mouse osteoblasts were imaged at beamline 01B1 at the National Synchrotron Radiation Research Center (Hsinchu, Taiwan). Collagen fiber orientation was observed in the lamellar structure of an osteon. Mineralizing osteoblasts were found to produce disordered mineralized nodules with varying density and structure.