Reconstruction of the hip joint by a saddle prosthesis after excision of a malignant pelvic tumor is a relatively new method, which thus far has been mainly used for revision of infected hip arthroplasties. One patient with a metastatic cystosarcoma phyllodes and one patient with a chondrosarcoma of the pelvis were treated by local resection and reconstruction with a saddle prosthesis. Although the patient with the metastatic cystosarcoma phyllodes died 9 months after surgery due to metastatic disease, both patients had early recovery, with no difference in leg length and obtained early painless complete weight bearing with satisfactory functional result. These two case reports clearly illustrate the usefulness of the saddle prostheses in limb saving surgery for malignant tumors of the pelvis.