Surgical treatment of malignant bone tumors of the pelvis with periacetabular involvement is constantly evolving. Even though acetabular reconstructions improve quality of life without impairing cancer control, they are not complication free. Our purpose is to describe the functional outcomes and surgical complications of different reconstructive techniques for Enneking zone II tumors. Fifteen patients underwent surgery for malignant pelvic bone tumors between 2002 and 2012. Seven patients were retrospectively evaluated according to the Enneking and Dunham classification and were found to have periacetabular involvement, as follows: 3 were type II; 1 types I + II; 2 types II + III, and one types I + II + III. Five patients had a standard chondrosarcoma and 2 osteosarcoma. Patients included 4 males and 3 females; mean age was 43 years. The minimum follow-up period was 12 months (mean 6.14 years). All of them underwent cancer resection with periacetabular reconstruction: massive osteochondral allograft in 3 patients, structural allograft and hip arthroplasty in 2 patients, and prosthesis with iliac anchoring in 2. They were clinically, radiologically and functionally evaluated with the MSTS scale (1993). The mean MSTS score 6 months after surgery was 20.71 (69%). Five patients (71.4%) had surgical complications: 2 dislocations of the native femoral head on the allograft; one aseptic prosthetic dislodgement, and 2 deep infections. All patients had free intraoperative borders. Acetabular reconstructions after oncologic resection for malignant bone tumors seem to provide good functional outcomes. However, only selected cases should undergo surgeries associated with a high complication rate.