Vertebral augmentation procedures are currently widely performed to treat vertebral compression fractures. The purpose of this study was to determine the frequency of underlying previously unrecognized etiology in a consecutive series of patients undergoing kyphoplasty to treat vertebral compression fractures. A prospective histological evaluation of vertebral body biopsy specimens from presumed osteoporotic vertebral compression fractures were performed in order to identify aforementioned causes. Over a 2-year period, vertebral body biopsies from 154 vertebral levels were performed in 75 patients undergoing kyphoplasty for vertebral compression fractures. All patients received a preoperative workup that included plain radiographs, MRI, whole body bone scan, and laboratory examinations. Bone specimens were obtained from affected vertebral bodies and submitted for histologic evaluation to identify the prevalence of an underlying cause. All specimens demonstrated fragmented bone with variable amounts of unmineralised bone, signs of bone-remodeling and/or fracture-healing. In 11 patients underlying pathology other than osteoporosis was identified (prostate cancer, 1; pancreatic cancer, 1; colon cancer, 1; breast cancer, 2; multiple myeloma, 3; leukemia, 1; and lung cancer, 2). In all but one patient the results of the biopsy confirmed the diagnosis suspected from the preoperative workup. For the last patient, namely the one with pancreatic cancer, the workup did not identify the origin of the primary tumor, although the patient was considered to have a compression fracture secondary to metastatic disease of unknown origin, the vertebral biopsy suggested the presence of adenocarcinoma which eventually was proven to be pancreatic cancer. In augmentation procedures for vertebral compression fractures, bone biopsy should be reserved for the patients where the preoperative evaluation raises the suspicion of a non-osteoporotic etiology.