Abstract: An apparatus for aligning an acetabular cup for proper placement in a socket in hip joint replacement includes a frame having feet which are placed against and fastened to the anterior superior iliac spines and the pubic tubercles respectively of the pelvis. A light beam is directed from a source through an aperture to a mirror mounted on an implant inserter. The light beam is reflected back from the mirror to a target region. When the incident and reflected beams are coincident, the cup is aligned for correct placement. The target region is rotatably and pivotably mounted for precise adjustment of the angles of abduction and anteversion respectively.