Twenty-eight unstable total hip arthroplasties were treated with an acetabular augmentation wedge. Of the hips, 23 have had no further dislocations at a mean follow-up of 26 months. Five patients continued to dislocate and have needed further surgery. To our knowledge this is the largest reported series of acetabular augmentation with as good results as those of the most successful reported series of this technique, and a success rate comparable to other methods of treating recurrent dislocation. Careful patient selection, and using a thin augmentation wedge to avoid impingement, are important to the success of a technique which is a useful option in the management of recurrent dislocation.