The results of revision of well-fixed Porous Coated Anatomic cementless acetabular components for polyethylene failure or periacetabular osteolysis in 18 hips (14 patients) are reported. Revisions were done with larger diameter cementless acetabular components replacing one-piece Porous Coated Anatomic devices for which no replacement liner was available. The objective was to determine the increase in size of the revision acetabular component and to assess clinical and radiographic outcomes. The Porous Coated Anatomic components were in place for an average of 7.8 years. At an average followup of 68 months, all revision components remain in place. Preoperatively, 12 hips in 10 patients had radiographic osteolysis, and 25 osteolytic lesions in 17 patients were grafted at revision. All grafted lesions showed partial or complete evidence of bone graft consolidation. The average revision component size increased 8.5 mm in diameter (range, 3-14 mm) compared with the primary component size. This corresponded to an average 6.5-mm increase in the acetabular cavitary diameter. When locking mechanism failure in a well-fixed cementless acetabular component prevents polyethylene liner replacement, acetabular component revision can provide good clinical and radiographic results with acceptable bone loss and improved access to osteolytic areas for debridement and grafting.