BACKGROUND Patients with spinal tumors are often referred for preoperative angiography and embolization before surgical resection to minimize intraoperative bleeding. OBJECTIVE The purpose of the present study was to investigate the angiographic appearance of a variety of spinal tumors, assess the safety and efficacy of preoperative embolization in relation to the amount of intraoperative blood loss, and correlate intraoperative tumor histology with the degree of gadolinium enhancement on spinal magnetic resonance imaging (MRI) and tumor vascularity visualized during angiography. METHODS Retrospective and single-institution cohort study. METHODS One hundred four patients with spinal tumors referred for preoperative embolization. METHODS Effectiveness of preoperative embolization in relation to intraoperative blood loss and number of transfused packed red blood cell units in perioperative period (72 hours). METHODS From 2000 to 2009, 104 patients with spinal tumors underwent 114 spinal angiographies with the intent to embolize feeder vessels before surgery. The effectiveness of embolization was compared with the documented intraoperative blood loss. Angiographic tumor vascularity was graded from 0 (avascular) to 3 (highly vascular). Ninety-four patients had a pre- and post-gadolinium-enhanced MRI of the spine before transarterial embolization. Magnetic resonance imaging vascular enhancement was classified as Grade 3 (avid contrast enhancement), Grade 2 (moderate), or Grade 1 (mild). RESULTS Transarterial tumor embolization was angiographically complete in 63 (66%) and partial in 33 procedures (34%). In 18 cases, the target was not deemed suitable for embolization. A limited statistical analysis did not reveal a statistical difference in documented intraoperative blood loss between patients with complete versus partial embolization for the entire cohort or when stratified into renal cell carcinoma (RCC; p=.64), multiple myeloma (p=.28), malignant (p=.17) and benign tumor groups (p=.26). There were no clinical complications associated with embolization. There was poor correlation between MRI enhancement and angiographic vascularity. CONCLUSIONS Preoperative embolization was angiographically effective in most cases. Avid gadolinium enhancement (Grade 3) on MRI was not predictive of hypervascularity on angiography. Furthermore, hypervascularity was not restricted to classically vascular tumors, such as RCC, as it was noted in some patients with breast and prostate cancer. However, with the available numbers, the quality of preoperative embolization did not significantly affect intraoperative blood loss. A future prospective randomized controlled study may be warranted to better characterize the benefits of preoperative embolization for spinal tumors.