Introduction:. Jumbo cups (58 mm or larger diameter in females and 62 mm or larger diameter in males), theoretically have lowered the percentage of bleeding bone that is required for osseointegration in severe acetabular defects. The purpose of this study was to analyze the safety and efficacy of Tritanium jumbo cups in patients with major acetabular defects (Paprosky type IIIa and IIIb) and assess the extent of osseointegration. Material and Methods:. From February 2007 and August 2010, 28 consecutive hips (26 patients, mean age of 69 years) underwent acetabular revision arthroplasty for treatment of Paprosky type IIIa and IIIb defects using Tritanium jumbo cups (Stryker, Mahwah, New Jersey). Results:. 14% of the hips had pelvic discontinuity. There was no intra-operative fracture. The initial stability was achieved in all hips, supplemented by screws. No Tantalum augments or bulk bone grafts were used in any of the cases. At mean follow-up of 4 years, there were no failures due to loosening or cup migration. Radiographic assessment showed osseointegration in all cups, ranging from 30% to 75% of the cup surface area as assessed in both anteroposterior and false profile views in Charnley zones I through VI. Discussion and conclusion:. In Paprosky type IIIb defect with pelvic discontinuity, jumbo cup can be used safely without the use of any augments. In pelvic dissociation, the fibrous tissue is stretched with jumbo cups in an under-reamed socket to achieve a fixation by distraction, especially in failed cemented sockets