Background Surgical treatment of pelvic tumors with or without acetabular involvement is challenging. Primary goals of surgery include local control and maintenance of good quality of life, but the procedures are marked by significant perioperative morbidity and complications. Questions/purposes We wished to (1) evaluate the frequency of infection after limb salvage surgical resection for bone tumors in the pelvis; (2) determine whether infection after these resections is associated with particular risk factors, including pelvic reconstruction, radiotherapy or chemotherapy, type of resection, and age; and (3) analyze treatment of these infections, particularly with respect to the need of additional surgery or hemipelvectomy. Methods From 1975 to 2010, 270 patients with pelvic bone tumors (149 with chondrosarcoma, 40 with Ewing's sarcoma, 27 with osteosarcoma, 18 with other primary malignant tumors, 11 with metastatic tumors, and 25 with primary benign tumors) were treated by surgical resection.Minimum followup was 1.1 years (mean, 8 years; range, 1-33 years). The resection involved the periacetabular area in 166 patients. In 137 patients reconstruction was performed; in 133 there was no reconstruction. Chart review ascertained the frequency of deep infections, how they were treated, and the frequency of resection arthroplasty or hemipelvectomies that occurred thereafter. Results A total of 55 patients (20%) had a deep infection develop at a mean followup of 8 months. There were 20 infections in 133 patients without reconstruction (15%) and 35 infections in 137 patients with reconstruction (26 %). Survivorship rates of the index procedures using infection as the end point were 87%, 83%, and 80% at 1 month, 1 year, and 5 years, respectively. Infection was more common in patients who underwent pelvic reconstruction after resection (univariate analysis, p = 0.0326; multivariate analysis, p = 0.0418; odds ratio, 1.7718; 95% CI, 1.0243-3.0650); no other risk factors we evaluated were associated with an increased likelihood of infection.