Human tooth enamel is composed 96% by weight of carbonated hydroxyapatite (HAP). It Js believed that the carbonate ions substitute for the phosphate ions in HAP, and it is expected that the carbonate will have an effect on the rate of dissolution of HAP during the carious process in human tooth enamel. In the present study high resolution electron microscope images of synthetic stoichiometric HAP were obtained to explore the possibility of obtaining direct structure images in HAP, and to provide a standard to which human enamel HAP could be compared. Bres et al have pointed out that structure images of HAP may provide a means of studying the substitution by carbonate of phosphate or other ions in biological HAP. The specimens were examined with a top-entry JEOL 4000EX HREM fitted with a Cs = 1.0mm objective pole-piece at 400kV. This 4000EX has demonstrated a structure resolution limit of better than 1.8 Å.