An interlocking nail having an hour-glass geometry is used for repair of bone fractures. The hour-glass interlocking nail includes a proximal section, a mid section, and a distal section. Each section of the hour-glass interlocking nail has a diameter. The proximal and distal sections each have a diameter larger than the mid section so that the interlocking nail has an hour-glass geometry. The hour-glass interlocking nail comprises at least one fixation aperture located within either the proximal or distal section of the hour-glass interlocking nail. Preferably, the fixation aperture has a tapered locking design adapted to receive a screw-cone peg. The hour-glass geometry utilized by the interlocking nail is better suited to address a larger population of bone canal geometries, stressing the fracture site with known values within the healing process and preventing inadvertent perforation of the nail through the cortex of the bone. Hour-glass nail geometry more appropriately distributes stresses and promotes better healing at the bone fracture.