Cup revision can be a highly complex operation depending on the bone defect. In acetabular defects of less than 30% (Paprosky types 1 and 2), porous hemispherical cementless cups fixed with screws give good results. Modern trabecular metal designs improve these good results. Morsellised allografts are useful for filling cavitary defects. In acetabular defects greater than 30% (Paprosky types 3A and 3B), impacted morsellised allografts with a cemented cup technique produce good results. Difficult cases with pelvic discontinuity require reconstruction of the acetabulum with acetabular plates or large cup-cages to solve these difficult problems.