Longitudinal sections and concentric layers of normal dog femurs were analyzed for their fluoride contents. Longitudinally, fluoride is deposited in greatest concentrations in the epiphyseal regions, i.e. the regions of vascularity and active growth. Concentrations in these regions are approximately twofold greater than at the mid-point of the diaphysis. In cross section, fluoride is also deposited in greater concentrations in the areas of more rapid growth and better blood supply, i.e. on the periosteal and endosteal surfaces of the shaft. The pattern of deposition is similar in adult and young bone, though fluoride concentrations are appreciably greater in the adult bone. The pattern of distribution conforms with the accepted principles of deposition of other boneseeking elements. Submitted on November 17, 1958